I'll tell you my experience. I started back in 2018 taking courses from Interaction Design Foundation. It is a great start to read about basics. Their annual fees is minimal. I learnt theory from there.
2nd is you can join any bootcamp that provides you an opportunity to work on a project while you learn. In my case I was good with theory but had no UX projects. So it really took time to me to connect theory with real projects, as I am not from a designer background.
I hope it helped. Ask me more questions if you have!