Screen turns off for a second every now and then and mouse movement doesn't match witch display poll rate

Hello, I use Ubuntu 22.04.2 LTS and I got a strange problem without knowingly changing anything: Every now and then my primary display turns black for a second and then back on. My secondary display is working fine. My speakers are also connected to the display, so I'll hear a sound from them when it happens. I can't make out exactly what causes the turning off/on, but when I don't touch anything, it happens less frequently than when I'm working, switches windows, etc. Furthermore while my display works well with 144Hz refresh rate, my mouse input works at a noticably much lower refresh rate. I tried restarting my PC and replugging my DP-Cable and power cables. I'm relatively new to Linux so I don't know what the causes could be. I hope someone can help me :)