You seem to be more interested and or inclined towards music theory. You are also on Lemmy, which means you are not technology averse. My last assumption is that you might be older (40+).

With all of those assumptions in tow, I would recommend something slightly different. I would recommend electronic music on a DAW like Abelton. Electronic music doesn’t necessarily mean “club music”. A lot of orchestral and acoustic sounding music today was mostly, if not fully, composed and performed electronically through a DAW.

So, why this approach? Put simply, you can learn it mostly from books and performing it does not require you to train your body, only your mind. Itbis also incredibly accessible. If you have a modern computer, and invest in small and new midi controller, you have all you need. I recommend an Arturia Keystep MK2. It runs for $169 and it comes bundled with all the software you will need to get started, including Abelton Live Lite, a slimmed down version of one of the world’s most popular DAWs. The Keystep is tiny and it has a ton of features you might benefit from later (sequencer, arpeggiator, chord lock, etc).

As you learn music theory, you can literally draw and adjust the musical notes with your mouse on the DAW. Music theory and a DAW is the most intellectual way to create and perform music.

If you prefer a more tactile and acoustic approach to music, then a Ukulele is a great choice. I recommend the “Enya Tenor Ukulele 26 Inch Carbon Fiber Travel Ukelele”. It looks cool, sounds good enough, and is weather resistant so you can take it with you anywhere. The damned thing is nearly indestructible by the elements (except extreme heat).