I have Galaxy Watch 4 and Pixel with GrapheneOS. Currently I have second profile with galaxy wearable and google play services for connecting to the watch. Before I've installed graphene I was using my watch as any other person, for notifications, sports, etc. Now I use it only for checking what time is it and developing apps. I can see my sports activity only for a week back, because samsung health only works on main profile.
Is there a way for me to use my watch on main profile without google and samsung apps? Maybe with some alternative app? Or should I sold my watch and buy a new one? I've heard good things about garmin and polaris? I would love option to develop my own apps on them.
Gadgetbridge is an Android (5.0+) application which will allow you to use your Pebble, Mi Band, Amazfit Bip and HPlus device (and more) without the vendor's closed source application and without the need to create an account and transmit any of your data to the vendor's servers.
EDIT: I just realized, that Samsung wearable devices are using WearOS, which is unsupported by Gadgetbridge. So your best options are either to stick with the proprietary apps or to check out devices, that have good support in Gadgetbridge. For example bangle.js, Garmin, etc.
it doesn't support any Galaxy Watches at the time I'm writing this, but if you end up picking another device, look into Gadgetbridge and which devices it supports: https://gadgetbridge.org/