Btw /e/ OS people have already shared that they were getting ready for a hard fork of AOSP looking at how Google is acting. But to be fair the challenge is more around the hardware support than the OS itself, so in the end it will be the chip makers which will decide which OS can run or not. If they go the AMD way then great, if they go the old nvidia way where even basic reclocking is impossible then we are screwed.

I would be surprised if they have the expertise and manpower to do that.

They are mostly relying on LineageOS now and putting their own cloud, microG, and App Store app and branding on top of Lineage. Even now they are not able to roll out Android releases and WebView updates timely. Them maintaining an AOSP fork would probably end up in an outdated, broken mess.

My money is on GrapheneOS and maybe LineageOS to do it when needed.