There are very good professional 4K monitors with PVA/MVA panels, which have excellent sRGB colors - but somewhat lacking in Rec.2020 colors gamut and peak brightness.
I have a BenQ PD3200U at work and it's absolutely stunning, even though it only has sRGB - which made me believe that good factory calibration is much more important than inflated 'gamut' and 'contrast' numbers.
The
newer DisplayHDR certified monitors should be above average in this regard, though still not up to high-end QLED and OLED televisions.
But surely most of these so-called 'gaming' monitors, especially those with cheap low-quality TN+film LCD panels, have very mediocre color quality, well below the boundaries of sRGB gamut, quite awful viewing angles, and introduce very large color uniformity errors, so they are far worse
than good CRT displays of the past. Avoid these at all costs, no matter how many stupid 'Hz' or 'dynamic contrast' or whatever they advertise.
The problem with CRT monitors is they cannot display anything higher than 1280x1024 pixels with a decent quality, even on very big and rare 19-21" professional models that weight quite a lot, and their peak brightness and contrast ratio is also not very good by today's standards. Not to mention they stopped making them about 20 years ago, so by now you can only find very old and used CRT displays.