First, discuss.grapheneos.org

If you have bugs, github.com/grapheneos/os-issue-tracker/issues

first I lost my fingerprint sensor

Same device, no problems, likely hardware problem

now with one of the more recent beta updates

have just screwed it up over and over again.

You may want to use the stable channel.

intermittent cell service issues in areas where I never used to have service issues.

Likely LTE-only mode, network settings. Keep it on if you care about using something without known security flaws.

I've been considering switching over to graphene for a while now

How can you consider it and at the same time use it?

Please just use their website, it should cover what is working and what is not using their sandboxed play compatibility layer.

Gmail works, avoid using their app, and just switch to a better provider. Privacyguides.org

That family link stuff idk, if it is invasive like parental controls it will not work.

but wanted some feedback on how that works when I'm not really trying to disconnect from the rest of Google services.

The OS makes no connections to google. Sandboxed play uses the same google code but as a sandboxed app. This will not give google any sensitive data or control over the device. Read and understand this thread

Will I have any issues if I switch using the same Google services?

Check gmscompat compatibility. Search for every thing you use in their forum or matrix (server: grapheneos.org), if you dont find it ask in the forum.

assuming Nova works just fine on graphene as well?

Yes it does. For paid apps you need sandboxed google play, have not tested that. Aurorastore (use session installer, dont grant file storage permission) doesnt require google login and services but may break in the future and is less secure.