Need Help - DIY laptop to desktop conversion

Hi everyone, when DIY perks posted a video about turning laptop motherboards into desktop pcs, I thought this was the perfect solution for me as I was in the market for a cheap gaming desktop.

I went and bought a Lenovo legion 7 16ARHA7 motherboard with a ryzen 9 6900hx and an rx 6850m xt for only $500. I was very distraught however when all of my parts came and I wanted to play some games the computer started thermal throttling ( prochot ext/BD prochot) after troubleshooting for weeks I decided to reluctantly return the motherboard, whenever I went to buy a new one. I saw that prices rose to $800-$1000. I had to buy the weaker (r7 6800H rx 6700m) version off of another seller for $400. When this new motherboard came (today) I was excited to finally have a working motherboard to do some gaming but whenever I ran stress tests the same problem occured (prochot ext).

Throttlestop is only supported on intel cpus

I have tried using x86 tuning utility to limit power draw but that didnt help 

I am using an oem lenovo 300w power supply 

I have only the bare motherboard without the power button, trackpad, battery, any daughterboards etc. All I have is RAM SSD and heatsink

Any help will be greatly appreciated,

Thank you