I bought a 4K monitor a few years ago. It's beautiful when displaying 4K, but I'm still waiting for Linux to catch up. I used in on a desktop and that worked mostly ok, but on a laptop with different scalings on the internal and external monitors it is hopeless. I'm not even trying to use both monitors at once, I just want Firefox to be scaled from 2x to 1x when I disconnect the external monitor (and vice versa).
I recently bought a new monitor for my office and explicitly avoided a 4K monitor for this reason, it turns out there aren't that many 27" 1440p monitors nowadays. I ended up getting a Lenovo P27h (comes with USB-C) and it works great.
For someone who knows nothing about Steam, can you say more about what the hardware survey means? If it doesn't indicate resolutions in actual use, what does it indicate?
Stats from Steam, Since Steam Is for Gamers only, you are only looking at Gamer focused survey, then of coz you get results where 70% of PC has dedicated GPU.
I have the best part of a decades experience with this. Until recently I was running 3 4K displays on my desktop.
The real issue is with DEs and not Linux per-se. Gnome handles 4K (Hi-DPI) better than most other DEs I've tried but it's still pretty horrid with Hi-DPI and non Hi-DPI displays mixed.
My rule of thumb has been to try keep all displays at the same resolution. For desktop that's easy, for laptop; buy a laptop that's 4K (not always cost/battery effective), or turn off its display when using external (loss of screen real estate) or change the external monitor to 1080p (not ideal, loss of resolution).
I recently bought a new monitor for my office and explicitly avoided a 4K monitor for this reason, it turns out there aren't that many 27" 1440p monitors nowadays. I ended up getting a Lenovo P27h (comes with USB-C) and it works great.