It's worth trying Dota2, you just have to be okay with losing a lot of your matches at the start until you learn the ropes.

I like to recommend Lina as a good hero to learn with, she has two strong AOE spells but can also build high regular attack damage. More importantly though her stun has a short delay which can really help you learn timing and predicting enemy movements. She's also a fairly squishy intelligence hero which can teach you safer lane positioning in the early game. She can be a strong mid but also a decent support or lane pusher depending on what your team needs.

While learning all the heroes is great in the long run I think it's best to stick with one hero until you get a feel for the game. After that any time you fight a hero that is dominating and feels completely broken just make it a point to try and play that hero next to learn its weakness.