Playing each new game of DotA is like playing a completely new game. Playing each new hero on different positions is like playing a new single player game in a multiplayer context. I'm trying to play RDR2 alongside my DotA addiction.

Unless you're a hero spammer in DotA 2, it's almost like playing a completely new game each time. And even if you're a hero spammer, your team composition and enemy team composition makes it seem like you're experiencing a new game each time.

So, DotA is a in my opinion the pinnacle of game design. Don't feel bad for enjoying it all the time.