It's surprisingly smooth, basically "just Android" but less bloat, spam, and creepiness. Way easier than my transition to Linux has been (which still wasn't bad), and I feel like I can relax now.
I AM mildly annoyed that I was unable to fully degoogle though. I need Android Auto which needs Play Services. And I need a navigation app, and the one I chose (Here We Go) works in Android Auto ONLY if downloaded from the Play Store specifically, not even Aurora. Literally the only app that did that once I enabled side loading in Android Auto settings, and literally the only app I needed to work on Android Auto. But it was either that or Google Maps from Aurora basically and uh...nah. I found Open Street Map based apps to be unusable.
Still, it's sort of nice to have the Play Store and Play Services. Play Store is most secure for downloads. Notifications are more reliable. I only give network permissions to each and turned off Play Protect so they can't phone home. Most things auto update between Graphene App Store, Droid-ify, and Play Store (Aurora and Obtanium can auto update on my old phone, but not on GrapheneOS). The stuff I have left in Obtanium are just a few game emulators which aren't security critical. I made a new burner account from the phone settings with a VPN on and it didn't ask for a phone number that way. I can make a new burner next time I get a phone. Or not, and I can buy Play Store gift cards with cash if I really need paid apps. I was starting to like Koala Sampler for example, though it does have a few trackers which I'm not comfortable with.
I'm also mildly annoyed that I had to overpay for the hardware just to lose my SD card slot. Gaming is unimpressive, it's barely an upgrade from a Snapdragon 865+. It definitely still has a premium flagship feel though, and the CPU and camera is a big improvement from my old phone.