npjohnson, first: many thanks for maintain pixel 2, hope for many mor LOS versions to come.Maps relies on Google Services I'm pretty sure. Wouldn't expect that to work.
Indeed, without GAPPs installed nobody should expect a working Google Maps Apk.
But what I can assure you: on LOS18 (on a Fairphone 2) Google Maps worked perfectly - also without any other Gapps installed.
Only now in LOS19&20 on my Pixel 2 this doesn't work anymore - only sometimes after another App manages the first GPS-fix which Google maps then can use. After this I also used it for 2h for routing. Therefore I hoped it should also work for the first fix - but how and why not?
Are there any non-Google-Apps/services which should bring the missing functionality to LOS?