I swear to gourd I had NEVER SEEN a 5:4 LCD monitor in my entire life as a child but now that I want to perfect my retro setup the ONLY MONITORS I can find at thrift stores are all 5:4. Like why. Who is responsible for this. I don't want to spend all the money on shipping a monitor from ebay but I'm losing it.

Congratulations, you're old. Everything is HD now, there's no reason to make those anymore.

If this is Linux, I'm pretty sure that you can use RandR (or whatever Wayland's analog is, if this is Wayland) to crop the visible area to whatever aspect ratio you want. Probably on Wayland the wlr-randr command can do it on wlroots-based compositors.

I've done so before on X11 with an HMD that extended into the edges of my visual field, where I wanted everything in the (crisp, clear) center.

searches

Looks like it:

https://man.archlinux.org/man/wlr-randr.1.en

--mode | --custom-mode     <width>x<height>[@<refresh>Hz]

Set output resolution and, optionally, refresh rate.

--pos <x>,<y>

Position the output with absolute layout coordinates.

It's gonna be for one of those computers that remakes the pc-xt with modern chips.

Edit: NuXT from monotech

A 5:4 monitor would be closer to square than an HD monitor. I'm not sure if the OP meant an HD size or actually 5:4 since I haven't seen anything that size except for digital picture frames and portable console screens.

5:4 was great. I could see a full screen video edge-to-edge, and still have room for a toolbar.

Today I have no idea why I would like that, but I did.

That's really weird. As far as I know there's only one common resolution that was 5:4, 1280x1024. Honestly I never understood why that existed when 1280x960 was right there.
But now that I think about it, maybe it worked better for businesses where documents took a lot of screen time and a little less scrolling was nice. That could explain how thrift stores got overloaded with them.

1280x1024 is a pretty common size for old LCDs.

I had CRTs that could do that, too, but if you opened a picture of a circle, it looked like an oval.

I'm not saying those screen ratios, or those resolutions, didn't exist, but I wouldn't say they were the norm.

Yeah, I don't think I've seen a native 5:4 CRT. I imagine it's a lot harder to make a different aspect ratio with CRTs, since LCDs are essentially cut out of a sheet, while CRTs are molded glass.

With LCDs, though, 1280x1024 was a fairly common native resolution. If you were getting an LCD above 1024x768 that wasn't a widescreen, it was almost certainly 1280x1024.

I had a 1280x1024 monitor which is 5:4. 1024x768 is a popular 4:3 resolution