Borderless FullScreen Wont Let Me Change Resolution + Obs Problems

[SheppardSG1]

Hello i have 2 monitors one is 28 inch with 4k the other is 24inch and when i select borderless resolution it will stay in native 4k on my primary one that i use for gaming if i select it to 1080p it will go back to full screen mode for some reason.
As for the obs problems goes i cannot put it on fullscreen with display capture anymore only if is in full 4k resolution on my primary monitor if i put it on 1080 it will just show it in small left corner on obs streamlabs obs man this game does not like obs hope you guys can fix that soon. Other than that its working smooth while i do normal gaming everything maxed out xd its just does not like that obs programs oh and i figure out that if you fly with normal arrow keys on your keyboard it does not stuttering anymore while recording or streaming it seems to do that only when you move mouse around. So i was trying to lower the sensitivity on my mouse to test it out if that will fix that but i cannot do that because it not letting me go fullscreen in obs for some reason in 1080p only in 4k where i cannot play this game because of low graphic memory xd Oh and selecting vsync off in nvidia controls settings like they are saying that it reduce stuttering did not help on my end Or i need to threat this game with C4 on it to might start working
Regards SheppardSG1

[CBJ]

The OBS issue you're experiencing is a known limitation of OBS; it does not fully support full-screen games running under Vulkan. You can either use it in windowed mode (where it can still cause some performance issues with sound handling) or use a streaming tool that does properly support Vulkan.

Can you explain your monitor setup in a little more detail as I'm a little unsure from your description exactly what you are trying to do and what isn't working?