We can buy things like courses, trainings, workshop tickets etc. and get that expensed.
Are there any recommendations?
Some noteworthy recommendations: Educative, O'Reilly annual subscription.
I find that video tutorials are better for learning ways to be efficient with tooling so random Youtube or conference videos work fine for me. Or even better, a remote pairing session with someone really strong in some particular tech!
Conferences and trainings are nice, but they are very expensive. I've been to conferences(because of my company) only when it was to do some recruiting and networking for the company I worked at. It's actually nice, you buy some sponsoring package and get a place where you can tell future applicants about the company. It's also a interesting network exercise. But then in 2-3 days your whole budget is used and the learning vs. cost can be low.
Also certifications(perhaps just the test) is a nice one. My company told us they would support us by paying the k8s certification and this is a nice thing to have. Might motivate some people to conquer something a bit more concrete.
One thing I wouldn't make is, make it mandatory, or that everybody must spend it in a certain event(like a conference). I've worked on a company that didn't really give us flexibility and that sucks. A lot of people function differently and would have better results if you just... let them pick what they want.