2 cents on this, DOTA 2 is a much more complex game, with almost the exact same soft skills. I hang out in DOTA more ofter, but every year or so a family memeber askes me to patch League and I am able pick it up like an old bike. The extra mechanics such as denying your own team, traditional vision mechanics (purchasable wards) and a different balance philosophy makes it feel like a professional hockey player shows up for their local beer league.

League is a good introduction to MOBAs, but its monitozation is bad, it has a stronger focus on map timings (IIRC dragon can make or break an early game) and most importantly, there is a surrender vote. DOTA 2 does not have that (your queue is a commitment, you cant walk away from games, without being labeled as toxic and being relegated to the bad sport queue), the learning curve is steeper, and while there are no requirements to unlock the roster, everyones design philosophy is that most everyone can carry (pos1) if you try hard enough.