[OatMilkLatte]

That is becoming less of a problem than it used to be. There are upscalers that can, with zero lag, take an RGB signal and output something over HDMI that a modern display can use. And there are certain displays (generally computer monitors) that can deliver sub-frame input lag with used with a good upscaler. It's not QUITE the same as playing on a CRT, but it's good enough for speedrunners of many retro games.

Such a setup isn't cheap, but it's far more reliable and space-efficient than a giant CRT.

[SmellyGeekBoy]

I recently purchased a RetroTINK-2X, which is an inexpensive FPGA-based line doubler. It works on a line-by-line basis (as opposed to frame-by-frame like most upscalers) and so lag is virtually nonexistent. I don't have any experience of the more expensive setups like the OSSC or XRGB but it works great for my old consoles.

That said, I still generally prefer to use my PVM CRT monitor for gaming for reasons already discussed in this thread. It really can't be beaten.