I went and did a masters degree in Ecology (well, Conservation Ecosystem Management specifically) during covid which I really enjoyed. A lot of it was completely out of my comfort zone after 20+ years in tech but a surprising amount did translate, such as the maths/stats and writing R code.

I felt it made me a better 'thinker' if that makes sense? Learned to be more critical (in a good way) and consider subjects I'd never come across before. I even went and created (and won!) a business pitch to a government org to handle some habitat surveys which was a great experience.