Paired with the polar h10 strap is a good place to start.
I used it for a little while, and quickly found that I could only breathe properly and consistently whilst I was watching/aware of my breath. As soon as I started 'working' my breathing went back to terrible.
Industry is firmly in C/C++ land and I'm trying to pivot towards a more embedded career, which would put me in more junior jobs without the political sway to say "lets try embedded rust and contribute back".
There's a couple forward thinking companies like memfault, but it seems to be the minority.
My degree was in CE so I've always played around with embedded projects, but actual design skills have stagnated from being in my field, which trends towards only developing smaller purpose built tools for internal use over products.