skin flute

I have no personal experience but I've heard people say that a saxophone is rather quick to learn to play at a level that it sounds good.

Piano/Keyboard

There are some very simple, affordable little drum machines out there that are a blast to just sit and bang around on. It's a good way to lightly start getting into rhythm and timing. It's also something that won't demand a lot of dexterity. It's an unconventional answer, but it's also something that can get you rolling on music without needing to read sheet.

Or if guitar seems up your alley but chording seems intimidating, bass guitar is a great intro to that world. You can learn all the fundamentals of guitar, and if it becomes natural for you, switching over to guitar is almost seamless.

Whatever you pick checkout Yousician if they have it. It's great for learning.

The recorder. It's easy to get started, there is a lot of good information online (look up Sarah Jeffery), and professional plastic instruments are very cheap. It also requires no special care and doesn't need maintenance, since it has no moving parts.

The downside is that in order to play larger recorders your hands need to stretch a bit, so I'm no sure if that is a problem if you have joint issues.

The other option is a hand ocarina, but it is very hard to even make a sound, even harder to make it clear and consistent. Also you need to play entirety by ear. It's a fun challenge, though.

Banjo has light action.

Clapping your hands