I’ve only heard of GrapheneOS (and that authy is insecure in the same breath, so I need better 2fa apps).
The biggest thing I can think of that I don’t want to lose is the Motorola gestures. I constantly chop to open my flashlight and twist to open my camera.
Besides that, I have never touched the rom before, and I have both wells Fargo and discover banking apps I use semi-regularly. The banking apps I could probably move to just doing their actions on the website, but that difficulty is something I would like to be aware of going in.
I also use Mihon (successor to Tachiyomi) so problems with that and solutions would be nice.
Yes, Graphene developers will not port Graphene to any other devices, because they’re insecure. You’ll need a new phone to use GrapheneOS.
It’s possible that your phone is supported by CalyxOS, which has a lot of the same degoogled feature, but a little less compatibility.