Could SteamOS replace Mint for everyday apps?

SteamOS has a KDE Plasma desktop mode, so it isn't limited to the gaming interface. LibreOffice, Discord and Firefox are available as Flatpaks and can be used there. You can also add non-Steam apps to Steam if you want to launch them from gaming mode.

Hytale is the one I'd check separately. The discussion doesn't establish how well it runs, so look at its current Linux support and installation requirements before switching.

What are you hoping to get from the switch? Steam works on Mint, and Mint is already set up as a general-purpose desktop. SteamOS is more gaming-focused, so I wouldn't replace a working setup just to run the same games and apps.

The hardware matters here. SteamOS is tailored toward gaming hardware, and compatibility on a regular PC can vary. The sources disagree about installation and support on non-Valve devices, with a newer installation image described as improving compatibility on some modern systems, particularly with AMD graphics.

Check the current support for your exact GPU and other hardware before installing. Desktop mode doesn't necessarily make it as straightforward to maintain as Mint, especially if you need software outside the usual app packages.

Bazzite is another option if you want a SteamOS-like gaming interface alongside a desktop on a PC. It's Fedora-based rather than Arch-based. Check its hardware requirements too, rather than assuming either system will work perfectly on your machine.