I want to change the camera resolution for screenshots so it takes photos in 1920x1080. I need this so I don't have to use third-party capture programs.
As far as I understand, the SnapshotCamera.txt file is responsible for taking photos. But I don't see any quality, height, or width settings there. The cameras.txt file doesn't mention anything about this. What settings should I change?

I don't think there's a way to do that through the default camera.
I'd think if anyone had done this yet, there would likely be a tutorial or a mod.

If you have Windows 10 or 11, you can use the Printscreen shortcut, and the screenshots are saved on your computer in a separate folder. No need for a separate screenshot program.
(For me it's the Windows button + printscreen).

I think the RPC has a separate screenshot function, but that one also uses the Printscreen button.

I forgot to add: it's also necessary to prevent the interface from being photographed (for me, the Tab key doesn't hide the interface in CAS mode and town view). How can I fix this? Is there a solution?

I think F10 hides it in most cases (not sure about CAS and hood view, but it works in build mode and live mode - only recently learned about this one myself, so haven't gotten around to test it much).

TAB activates the cameraman mode, it technically isn't an interface hider.

You can use the "No pause line" mod https://modthesims.info/d/586548/no-pause-frame.html for the red line.

The only thing I so far haven't been able to remove is the version number to the right, but I think that only shows when the game is in debug mode (which mine always is), but I usually make sure it's easy to edit/crop out.

[totally unrelated to the original topic- but]
LazyDuchess' RPC launcher mod, or the RPCLib (if you just want the fixes and features without the launcher), hides the debug mode version number.

I know, but it doesn't bother me much.

Oh okay, I only posted because you said you hadn't been able to remove it.

Haven't really tried, to be honest. Mentioned the version number just in case OP might wonder about that one.

Vaguely remember RPC did have a mention about removing it, but I've had enough trouble with my game, I haven't felt like gong through all that again just for the RPC (which I know has some decent stuff in it, but also a few things I'm less interested in). I've gotten around the version number for some 18-20 odd years, it's no biggie