Problems with Alienware Graphics Amplifie

I am using Alienware 15r3 + Alienware Graphics Amplifier with RTX 2060 Super connected to external monitor. I have run into multiple problems. Ubuntu 21.10 installs with nouveau drivers as default. Before changing the drivers to official ones I have to change gdm to lightDM (if not my system becomes unbootable). I can’t install the 510 driver (from Softare and Updates) because it makes my system (again) unbootable. I can succesfuly install 470 nvidia drivers but my external display stays blank. I can see that GPU is detected in lspci but when I run nvidia-smi it says that no devices are detected. Does anyone know whar can cause the problem and how to solve it? I am frustrated because I have been fighting with it for 5 days and need my PC functioning ASAP. Thanks in advance