Totally. I'm a piano player. With piano, it feels easy because I started at three years old. But with guitar, I have to really challenge myself the way you're describing. Especially, I bought a pedal steel slide a few years ago. It's a "basic" one with 3 pedals, 12 strings, 2 knee levers, but still the most complicated musical instrument I've ever met. Playing it is the closest feeling I get to being
really in the flow when writing code. If I had to define this feeling, I hate to use this term, but it's like a really fast REPL as you play, where you're trying to inject your creativity but also mathematically translate what you're about to do into four different limbs at the same time. It's
way harder than piano, to my brain. But also deeply satisfying because it's not a reflex, it requires constant thought.
Maybe if it ever became a series of reflexes, I would have to move on to an even more complicated instrument?
On a side note, learning a new language is an amazing way to keep your brain active too. And learning a new instrument is a lot like learning a new language.