I just switched to LineageOS 18 w/ MicroG and oh my lord is this stuff still complicated. I'm fairly familiar with this stuff and yet still it took me many hours to set everything up correctly. To be clear, this is not the fault of LineageOS, this is simply the state of the FOSS Android environment and the fact that Google has no interest in supporting this setup whatsoever, to put it mildly. Not only is it complicated, it also seems to change pretty much every year.
First the question is how to transfer all your application data, for which there still seems to be no surefire way. I settled on "Neo Backup", which mostly worked fine, except for Signal (of course...), and the darned Microsoft Authenticator.
So first unlock the bootloader (good luck), then you need to find the correct TWRP for your phone (and careful with 32/64 bit) and flash it via fastboot.
Then I flashed LineageOS, which worked fine. Luckily I found an image which already had the signature spoofing patch included, so I didn't have to worry about that. How do you get root? SuperSU? XPosed? Magisk? OK it seems everybody's using Magisk nowadays. OK, flashing worked fine, but now, how do you get MicroG on it? If you look at the MicroG homepage, you might think you can just install it with F-Droid, and you actually can, but many things won't work (like FCM notifications). It needs to be a system app. I tried using the F-Droid Priviliged Extension, flashed it via TWRP, which seemed to work fine but actually wasn't installed and not working at all. Now what? There's a multitude of information in forums what to do. Some say to flash NanoDroid, but the last release was in January 2021, it seems it's not updated anymore? I settled on the "MicroG installer revived" Magisk module, which worked fine (btw, there's no curated Magisk module repo anymore, you have to search the web and hope you find something that's not malicious).
Of course my banking apps refuse to run because "U ROOTED UR PHONE", I search for Magisk Hide, it doesn't exist anymore, now you need to configure a "Zygisk deny list", whatever that is. Then I also need to hide the Magisk app, my banking works now thank you very much. FCM notifications also work after I uninstall and reinstall my apps which need it...
To be clear: I'm eternally grateful to all the developers who make this possible in their spare time. This is not their fault.
I've been through much the several journey several times, each separated by enough time that I have forgotten all the little details.
I eventually found out about LineageOS for MicroG [1] which is a variant of LOS with MicroG bundled which cuts out most of the fooling around, removes the need to root my phone and works with both banking apps that I've tried.
After hesitation, I opted to go full on the "privacy above all" path - out of curiosity if it was possible and bearable.
So no root, no GFS or substitute at all. Only tracer free apps (except my bank) and using browsers.
I use a set of privacy add-ons (canvas fingerprinting etc) for wandering on the web and the "WebApps" app to isolate the web sites I use regularly and where I need to log into my account.
Then the TrackerControl app lets me allow or block connections per app and by destination.
Of course, this choice implies to renounce certain services without a web version, but I'm happy with the tradeoff (less time spent procrastining by consuming social networks content).
It's a bit annoying at first but I paid $80 for this secondhand phone (including a good new battery). Within weeks I didn't notice anymore that speed difference with a native web app.
That difference of speed exists, of course, but I'm fine with the whole tradeoff.
Not being at all a security expert, I did my best - following advice found on the net.
How far is my privacy better protected though? I can't really know - that's my only true frustration. I see very few ads and they look poorly targeted.
Well, sorry for the long post, this was just to mention another possible path: no GSF or substitute at all, no root.
If you're going to that level you should also consider your phone always compromised and unsuitable for running a banking app. Humans got by without them for a long time.
I really like LineageOS, but this is partly on them as well. They are the most popular ROM and they do very little to make this situation easier. With this situation I do not mean the install itself - actually there they do a lot, the documentation for officially supported devices is really good (and you often do not need TWRP anymore, the lineage recovery is cleaner). But I mean everything else you mention: Rooting, Play services/MicroG, fighting against the security theater. They even officially ban talking about this and other impending topics of doom like VoLTE on their subreddit.
I do like what the project achieved, but I don't understand in the slightest what they are thinking. If I were to speculate, to me it feels like a leftover from their failed attempt to make this a business to ban everything some corporate partner might dislike. But what purpose would that serve for the project now? Just baffling.
Just flash ‘LineageOS for MicroG’[1]—it already has F-Droid extension & obviously microG. Recovery images are provided right alongside, though of course you can use TWRP if you prefer but you don’t have to. IDK why you need root, but most people don’t need it. Push works just fine with microG alone, you just have to enable it in settings. Also LineageOS has an integrated backup solution now.
As far as the rooting-related problems go, there's very little reason to root an Android phone today (unlike, say, 6-8 years ago). Most of the things you used to need root for now have a working API (like VPNs).
Magisk Hide was replaced with "Zygisk DenyList". Which is fine, my main complaint is that you cannot guess from the name that it is doing essentially the same thing. The reasons for that can be read here:
I'll add to the list: Advanced Charge Controller, and the ACCA GUI app for it.
This provides fine-grained control over battery charging if the kernel/device have the required features. The user can set limits on current, voltage, and percentage, as well as pause charging when the battery gets too hot. These settings can be saved into profiles selectable with a tap or on a schedule.
Limiting charge speed/capacity can significantly extend the service life of the battery.
> Doesn't unlocking the boot loader delete everything?
Exactly. Even if the phone is already unlocked, the official LinageOS installation instructions explicitly say to do a "Format Data / Factory Reset" in recovery before sideloading the OS.
First the question is how to transfer all your application data, for which there still seems to be no surefire way. I settled on "Neo Backup", which mostly worked fine, except for Signal (of course...), and the darned Microsoft Authenticator.
So first unlock the bootloader (good luck), then you need to find the correct TWRP for your phone (and careful with 32/64 bit) and flash it via fastboot.
Then I flashed LineageOS, which worked fine. Luckily I found an image which already had the signature spoofing patch included, so I didn't have to worry about that. How do you get root? SuperSU? XPosed? Magisk? OK it seems everybody's using Magisk nowadays. OK, flashing worked fine, but now, how do you get MicroG on it? If you look at the MicroG homepage, you might think you can just install it with F-Droid, and you actually can, but many things won't work (like FCM notifications). It needs to be a system app. I tried using the F-Droid Priviliged Extension, flashed it via TWRP, which seemed to work fine but actually wasn't installed and not working at all. Now what? There's a multitude of information in forums what to do. Some say to flash NanoDroid, but the last release was in January 2021, it seems it's not updated anymore? I settled on the "MicroG installer revived" Magisk module, which worked fine (btw, there's no curated Magisk module repo anymore, you have to search the web and hope you find something that's not malicious).
Of course my banking apps refuse to run because "U ROOTED UR PHONE", I search for Magisk Hide, it doesn't exist anymore, now you need to configure a "Zygisk deny list", whatever that is. Then I also need to hide the Magisk app, my banking works now thank you very much. FCM notifications also work after I uninstall and reinstall my apps which need it...
To be clear: I'm eternally grateful to all the developers who make this possible in their spare time. This is not their fault.