Originally posted by Schmowu:

GPU below 95% usage, the bottleneck is something other.

turn VSYNC OFF .....
after this your CPU need more singelcore power.
you have a 8core/16thread cpu? 100/16=6,25% CPU usage over 6,25% and it CAN not must be the bottleneck.

Of course, vsync has nothing to do with it because it's not even capping that. The bottleneck is the game. If it was Forza Horizon 5 I'd understand but that will prolly run just fine in 4K Ultra.