I remember something similar for the Acorn Archimedes back in my school days (late 80's early 90's). There was a switch allowing you to toggle between colour and green screen. No idea what the model number of that monitor was (wouldn't be PC compatible anyway I assume) but I'm surprised that the PC had something close to that.

Extremely rare for a VGA monitor to have such color changing switches. Most often these existed on multiformat color monitors to select the color when using monochrome outputs such as MDA.

I know an IDEK model that had such color masking switches.

I had an Idek with those switches, but no combination of those that would give that blue effect. I think you're probably thinking of a TVM monitor, they had a switch that alternated between green, amber, and a blue background with either white or yellow text (it's been a while) that was supposed to relieve eyestrain or have some other benefit. Most of the the TVM monitors I saw in in the wild were CGA, but there is the TVM MD-11. It is a multisync monitor that does 15-31kHz - so CGA, EGA and standard VGA (640 x 480, but no higher). This would have been an really old monitor to be using in 2001, but back then I was still running an NEC multisync of similar vintage on one machine and a monitor with no case that came out of slot machine on another - you take whatever you can afford that works 😀

something like that?

this is an EIZO 8060S