Okay after testing I can confirm that its definitely an cpu bottleneck. Seemes like the game or the unity engine is not capable of utilizing all cpu cores which is a bummer… I couldn’t find a workaround either. Even "taskset" via terminal does not help since the command shows that already all cores are allocated to the process. However the engine / game does not utilize these.

After some further research this is also my best guess. It looks like the game cannot utilize enough cpu cores. I will try to max out the settings to confirm it. However is there a workaround to utilize more cpu threads?