Been using 4k 28 inch for a few years now for gaming, couldnt go back to lower resolutions. I got one at work also and all my colleagues wanted one as it's much better viewing for work. You can change the icons size etc in windows - yes there maybe apps that don't scale well but that is the app not the monitor. Size, just changes how far you sit from the screen at the end of the day.
4k monitors are now coming out with 144hz refresh rates but unless you ahve high end PC hardware you'll not get anywhere near the framerates and these monitors are very expensive. Consoles don't do high fps either so a high refresh rate 4k monitor isn't going to be beneficial for you. Work wise they are a no brainer for screen real estate, unless you have poor eyesight or what app you need to predominantly use doesnt scale well then maybe not for you. Many 4k 60hz monitors now have Freesync so will take advantage of VRR.
We are now seeing TV's with higher refresh rates and VRR compatible but these are expensive as like 144hz 4k monitors they have only been available relatively recently.
XBOX gaming - I don't know if these output @ 4k? If so a TV would probabaly be better and less expensive. PC gaming I wouldn't have anything else other than 4k.
Don't forget with gaming benchmarks EVERYTHING is turned up to max to make the comparison easy to replicate, but will give low fps scores. All those game settings are there to get a decent quality image with frame rates that are acceptable to you from your hardware.
Looking for a new 4k 144hz monitor myself now but trying to get my wallet to agree to the still relatively high prices.
Recently there have been some 32 inch and 43 inch 4k monitors but these are new and so are the prices. In fact all the high hz 4k monitors are overpriced for what they are - they are priced for enthusiasts.
One website someone else posted recently I found handy to see what was coming up, is this one;
https://www.displayninja.com/new-monitors/