Have you tried things like adjusting setting on the display itself?
Is this the only prblem where 16bit and 32 bit look the same? If it is I'd say the monitor is at fault.
Why not treat urself to a new graphics card too.
OnePlus 5 review
50 best online Adobe XD tutorials
iPad Pro 10.5in (2017) review
Comment connecter un MacBook à une TV ?