I bought it used, and with the expectation that I'm going to be on the hook for my own long-term maintenance and support, as is true with more or less everythin

I bought it used, and with the expectation that I'm going to be on the hook for my own long-term maintenance and support, as is true with more or less everything I buy. (Full-time Linux user here.) The sad reality is that the experience of running an off-brand phone with an easily-replaceable battery would, long-term, be much worse than running a locked-in flagship that LineageOS builds for.