LineageOS4MicroG is a reasonable starting point. It includes MicroG out of the box, while disabling further app spoofing in the OS (whereas normally if you install MicroG yourself it’s much more difficult to disable app spoofing after you’ve got it set up).

But as /u/baatliwala@lemmy.world said, this is more likely adding Google (or a mock version of it) to your phone, and LineageOS still doesn’t have a few things that other custom ROMs might - eg captive portal check, A-GPS and DNS settings that /u/afunkysongaday@lemmy.world mentioned. To get rid of those you’ll have to try a proper custom ROM and just read the feature specs. I use DivestOS, and that seems to cover most things.

In my experience, not all that many apps require Google anymore. I get a few apps complain that they won’t work without Google services, but find that it’s just the map and payment functions that don’t work (meanwhile dedicated map apps like Waze work just fine). Going without Google services altogether is really just about sacrificing a relatively small bit of convenience.