I hope nobody here is assuming otherwise. This part of the thread was in reply to @helmutr who (I think) was trying to find a way to keep using several old Apple monitors that use connectors no longer provided by Mac computers (ADC and DVI).
And the answer is that adapters exist, but in this particular case, they may be expensive and/or hard to get.
For someone looking to buy a monitor for a modern Mac, they all have USB-C ports and some have HDMI ports as well. These can be used with inexpensive cables/adapters to drive monitors that use HDMI, DisplayPort (mini or full-size), single-link DVI and VGA ports.
Which means you can go to any store that sells computer displays and pretty much use any model they sell. You can also use a TV (definitely a 1080p HD TV, and probably also a 4K TV) via HDMI. But you may find that computer displays provide a better picture.
Personally, I would recommend looking at the least expensive display that has an IPS panel and the size/resolution you require, then read some reviews to see what people think of them.
I wouldn’t even look at an Apple monitor. If you need something like that, then you probably shouldn’t be asking me about it.
For myself, I’ve been buying Dell Ultrasharp monitors. They’re not the cheapest, but they’re good quality and they last a long time. The one on my main computer (a Dell 2405FPW) is over 15 years old, is attached to its third computer and is still working great.