Desaturated colors when using graphic acceleration

Hello!

im running a 2016 MacBook Pro with Radeon 460 GPU, latest Mac OS X Big Sur and photoshop 2021 (updated). 

whenever I am connected to my external monitor (calibrated) images in photoshop looks desaturated. Sometimes when zooming in it's even flickering between low saturation and normal saturation. 

when turning off gpu accerelation the colors looks normal but scrolling and zooming on the image is extremely slow. I would say unusable. 

I've been in touch with support but they couldn't help me. They said I need to update my GPU but I don't know what that really means so I'm checking with the forum. Everything except photoshop works including Davinci Resolve, capture one etc.

Any ideas? 

thanks!