Currently I am about my arm's length away from the TV, and I don't have particularly long arms. A bit thick maybe, but not long. I am not using it as a monitor at the moment though, but using the computer near to it and watching the TV at the same time. They are airing the old Tommy Lee Jones movie "U.S. Marshals" which is kinda shitty. Not the picture, but the movie.

Anyway, I have used it also as a monitor for my RPi4 and being quite close to it, using the 1080 resolution, and never I felt "Wow those pixels are HUGE! My eyes!". Sure, my eyesight might not be what it used to be when I was 15, but then I do use reading glasses if necessary.

Anyway, to each his own I guess. I am fine with the 1080 resolution both on my 27" monitor, and my 65" OLED TV.

Yeah, I recall this becoming a huge issue for me playing e.g. System Shock 2 in higher resolutions, when the user interface and all the text became very tiny, I had hard time reading the text...

In the end I think I ended up playing it is a very low resolution of 800x600, which is probably about the resolution the game was originally designed for anyway. Running it is higher resolutions didn't make it look particularly better because all the objects etc. were so low polygon and low texture quality anyway, so all you got with higher resolution was less jaggy polygon edges... and tiny text and user interface.

Sometimes modders can patch that and NewDark added the ability to scale in System Shock 2 and Thief 1-2 by editing the cam_ext.cfg file in the game folder and changing the d3d_disp_scaled_2d_overlay setting, so ironically it's now HiDPI aware. Some others source ports (eg, GZDoom) can scale well and Kentie's Launcher added scaling to Deus Ex. Problem is, in the bigger picture of things only a relative few such old games have received that treatment and there are many older games that you will have to run them at a lower resolution to keep them playable / text readable.

To add to this; I use a 1080p projector with a 100" screen and sit 2,5 meters away from it (yes, I measured). I use it for gaming and movies. I don't have the eyesight of a 15 year old either, but with contact lenses or glasses on I think the image looks pretty good.

great....now all i can think of is this.
https://www.youtube.com/watch?v=OiYOa9Me5LY
https://d1sb2vhc1h1lwk.cloudfront.net/designs2/136606/Preview/36538b/display.jpg

I would go for the 23.8 inch 144 Hz version

I use one. It's totally fine, don't worry. There're no visible big pixels.

It depends how close you intend to sit to the screen. For extremely close use I'd go with a 24" 1080p option, but if the screen's more than 30-40cm away from your eyes then 27" is not going to look that bad either.

Having a smaller monitor up close and using lower resolutions helps you save money on a GPU, helps you keep your electricity bill in check and is a far more economically sound option. Gaming (casually) is not about 4K or 8K folks, or about 500Hz screens, let's look beyond the marketing madness here.

I did had to purchase distant worlds universe again on steam (i found a discounted key for only a couple of euros) since using dpi scaling settings did not work on gog's supplied exe. Talk about finding solutions..... then again, the most popular games do come with all kinds of solutions. The less popular.. well that is up to the user i guess, though personally I do find myself in the same sentiment... like "considering UI scaling as a factor for what new display i would buy, huh?" many retro gamers on the other hand...

Just a quick tip for the future. GOG installs many games with a pre-set compatibility flag that ignores the OS scaling settings. You can disable it by right clicking on the game's .exe and unticking "Disable display scaling on high DPI settings". Alternatively, these settings are stored in the following registry keys:-

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers

Where if you edit the game's entry and delete HIGHDPIAWARE text, it will have the same effect.

Sorry I meant right-click on the game's .exe -> Properties -> Compatibility tab. It should be there (the same place as "Run in 256 Colours", "Run this program as an Administrator", etc).

Actually that option is greyed out. Maybe that will mean the program is beyond saving?

Try clicking "Change settings for all users". This takes you to a similar looking page that overrides the first one that changes it for every account on the computer.

In the past, I've used 1920x1080 on a 21.5 inch screen for many years. That spoiled me, when it comes to pixel density. I later upgraded to a 24 inch 1440p. It was my favorite option so far (not that many monitors with this size/resolution combo out there though), but due to some other issues with the monitor, I finally landed on 27 inch 1440p. Which is a very good middle ground and 27 seems like the perfect fit for 1440p.

Bus as said, this is all subjective. To me, 24 would be pushing it for 1080p, for others, it's completely normal.

4K is a resource hog, first and foremost. I'll always take a higher refresh rate over 4K. Which is the reason I am currently sitting on a 1440p, 27 inch, 240 Hz display.

Usually with retro gaming the UI stays proportional to the rest of the game's screen area, so the display's native resolution only determines how big horizontal borders you have to tolerate with integer scaling.

Playing System Shock in SVGA on a 486 back in the day got me so used to single digit frame rates that I still tend to always prefer higher details over the frame rate, for example I recently finally got my first 4K display instead of upgrading my 1080Ti as now I can play older games with 4K while with newer games 1080p is going to perform better than 1200p on my old display.