Korea is something I have on my mind for so long. I would love a detailed blog post regarding your experience living in Korea as an expat with breakdown of cost and how you ended up there. Seems like an interesting journey to know about.
Oh, that's one thing that might make it harder for the OP. Forgot about that. Before COVID, people used to do "visa runs" to nearby countries so they could stay more than 90 days (tourist visa).
I have an F4 visa that allows me to stay in Korea for up to 3 years, and it's simple to extend without leaving Korea. Technically I have almost all the rights as a Korean citizen except for the right to vote for president. (In practice it's more limited. For example it's nearly impossible for me to get a loan.)
With the F4 visa, I can work or not work. The F4 visa is granted to people who have relatives who are Korean citizens.