Performance below what I expected

[Booklordofthedings]

I have performance issues, specifically in league of legends.
I am not sure wether they are exclusive to the game, but most other games seem to perform fine, to the point where it doesnt matter.
Only league performs at a level that I would consider unresonable for my specs

My specs:
AMD Ryzen 5 2600
AMD Radeon RX Vega 56

2 * 8gb DDR4
1440p 165hz main display fr
1080p 60hz graphics tablet secondary display
wireless keyboard
wireless logitech mouse at 125hz

Drivers are up to date according to the amd software

 

The game performs at lowest settings (no vsync) at the start of a game with around 100-120fps, which is what seems resonable,
however when the fight starts ("first wave") it drops down to ~60.
The load on both cpu and gpu is low and on the ressource monitor the cpu cores dont even seem to be nearly full.

I have tried to disable the Highprecisionenventtimer thing in the device tab, which was suggested somewhere else but that didnt have an effect.
I have plugged an old school style mouse in, since I found that a high refresh rate for the mouse causes even more lag, but that didnt fix it.

I dont play many other games but those report far better fps for a similar amount of ressource usage
Gunfire reborn has 60-90fps
R6 has is pretty stable 130

Attached are 2 screenshots of the task manager while running league and the ressource monitor while running league

[Cyberat]

Windows since 2014 auto manages which GPU runs, so, you want to disable that Radeon Vega in Bios, so as not to have problems with games that don't select the correct GPU (or windows will not handle it). 2x Displays running different VRFs is another issue altogether.