Just kind of curious if anyone’s attempted to mod Sims four on the steam deck yet. May not be the most ideal setting, but it’s the only option I got right now. Would like to do some mods if I can find some. But I didn’t know if anyone’s had experience modern steam deck version, other games like Final Fantasy seven remake and American trucks simulator and so on.

There may be limited support for tools like Sims4Studio on Linux, but even a quick google shows how some people got it to work decently.
It would largely depend on what kind of mods you are planning to make. Pure tuning can be done in TDESC Browser and then packaged with S4S, which skips over performance issues the latter may have on an unsupported OS.

Or if you're referring to using mods in general, that part should be fine.

Yeah moreless just using mods that others made

Just for future reference, the Create forum is centered around how to make mods- that's why I started with that info

From what I understand of the Steamdeck, it really shouldn't be too different to modding on PC- given that it more or less is one. You'll likely be able to use all standard mods just by installing them in Desktop Mode.
It's also harmless to test it yourself.