This is already an issue on current monitors (and VR for that matter) - even HDMI 2.1 monitors needs DSC for 4k 144hz 10bit without chroma subsampling. And HDMI monitors come with a lot of downsides like no sleep/wake from port. (turning on the PC can automatically turn on your monitor if connected via DP but not via HDMI)

And DSC adds around 10ms of input delay - this was tested by hardwareunboxed, tftcentral and some other credible sources by using screens which enable DSC only in their highest refresh mode. The delay from clicking a mouse button to showing something on screen actually went worse going from 100hz to 144hz. They then tested it with a 1hz difference to barely bring it over the threshold and DSC added around 10ms on average. This might be even higher if higher levels of compression and decompression are required. Considering most high end gaming monitors with very high refresh rates (175hz/240hz) already only have around 20-30ms of total click to image latency this means DSC increases latency by up to 50%. This is A LOT especially for competitive games and rhythm games (MANY rhythm games have a "perfect/marvelous/flawless" timing window of 15ms which means that's a delay of almost the entire flawless timing window hence it's very much perceivable by people).

And as I said: higher refresh rates DSC might add even more delay. 240hz 4k screens are starting to become rather affordable at just 1000 bucks (which is less than a high end GPU these days but you tend to keep a monitor much longer than a GPU). Once the first proper DP 2.0/2.1 monitors show up early 2023 it will be really awkward to buy one with a 4090 because it will have to default to 1.4+DSC instead of using the 10ms less delay 2.0/2.1 connection. It's the main reason I didn't buy a 4090. I really hope Nvidia adds DP 2.0/2.1 to their refresh line (4080ti/4090ti) - if not I will definitely go AMD this gen. I mean on my 3080 many games already run above 120hz at 4k with high settings and without using upscaling methods like FSR/DLSS. And even 4k 120 444 10bit it too much without DSR unless you go down to 8bit. Considering even Intel ARC GPUs which don't need DP 2.0 with their performance already have that standard (it's royalty free so no licensing fee unlike HDMI 2.1 and the port itself is cheaper than 2.1, too) the 4090 is only using the old 1.4 port to give you a reason to upgrade to a 5090 next gen or upgrade to a refresh like the 4090ti down the line. It's disgusting and far more people should point that issue out instead of defending a company which doesn't care about them whatsoever just because DSC exists which is a lossy and latency adding tech. Personally couldn't see any difference image quality wise but the delay is very noticable on my screen when I want to go for 4k 120hz 10bit. Hence I want to upgrade to a DP 2.0/2.1 screen as soon as it arrives in early 2023 (announced by many companies like LG, Acer, etc. already) and need a GPU which supports it.