my 2017 mac air is getting real long in the tooth. I'd definitely considering switching to *nix with it but everything I keep reading is that process is not so easy.

I've been on linux since 2014; I'm an ocassional user of windows, booting into it with much regret to deal with client's issues. I generally dislike working with MacOS... but for someone used to macOS I see no meaningful degradation of the kind there is with windows - your time is better spent earning/buying/setting up an m series mac air.

Write a strongly worded letter to the manager (apple). It's easy on other hardware.