Quite possibly, the GrapheneOS team seems to think so:

https://grapheneos.social/@GrapheneOS/114665449554083676

https://grapheneos.social/@GrapheneOS/114665441933500613

Aren’t other forks going to be affected by the same issues?

Thanks, that doesn’t sound quite as bleak as I initially thought but it’s still not good.

They say they reckon they can still do an Android 16 release, but I assume these changes aren’t just for the major releases and its going to make even minor updates much more difficult now?

Any idea what the other upcoming changes to the AOSP that they mentioned might be?

Not much better but I’d trust Apple over Google any day. GrapheneOS is the only reason I switched to Android

Of course this would happen just after I sold my iPhone

You appear to have a road blockage!