GOS has made the statement they won't lie, spoof, or otherwise misrepresent the runtime environment. That means lazy apps who just turn googles safety and security knob all the way to 11 will refuse to run on GOS.

my banking app already won't let me use zelle on main profile without the g00g stuff. works okay on the profile with it though

I'm not a dev, so kilos of salt, but I expect it to make grapheneos and side loaded apps largely unusable or extremely compromised, without devs serious and quick attention. If you can afford to support the devs, you may consider doing so.

I'm not that concerned. There is also microg

"To be clear, developers will have the same freedom to distribute their apps directly to users through sideloading or to use any app store they prefer."