Things NOT to get:
TN panels of any kind. Their color rendition varies on viewing angle. IPS and its variations (including PLS and AH-IPS) is what you want.
Any monitor that isn't at least specified as 100% for the colorspace you want to work in. Might calibrate to 98% or so of it... still, far better than a design that does not try.
Monitor(s) your PC ...
I do not mean to get the cheapest one. I mean to define what a monitor/features you want and are worth for you. Are you running a studio for fashion photography for a magazine? Or it is a hobby.
In my opinion, the best monitor to have is the one you can purchase now and not in an undefined future.
Yes, size matters. Are you ...