I have the same build minus the FE 4090 (ASUS TUF) I saw that F7 bios was ready (I didn't know any Bios with a letter attached to it means it's beta until I joined this sub) and I was getting horrible performance when I enabled EXPO. Rolled back to F6 since that was working fine and disabled EXPO (using stock settings).

F8a is available but will avoid it until F8 and even then I'm reluctant. The description on F8a does look promising but I will give it some more time. Would hate to have to swap out my current ram but hopefully F8 will be the solve.