Are these battles in league content supposed to take 20+ minutes?

So I tried to play league content a bit while leveling. Got myself into battle that laster ~20minutes. Is this the intended league mechanic?..

Enemies seems to respawn super quickly, and the timer doesn't increase, even after I killed like 20 waves of them. It does feel like a complete waste of time.

Though it will feel much better with 30million dps when I can simply 1shot enemies. But with low dps it's completely anti-fun battles.

Didnt mind the massive battle I thought I lost but came back to win in the end.

i don't mind the long battles (but then again i am a moba or auto battler fan) however i do wish they were much more rewarding.

had a back and forth fight where i eventually won probably 15-20 minutes and i got 1 chaos for it as the outcome and barely any exp. mind you i was low level (about 30ish) but still

I cant say for sure for this league, but usually it means you have to get a stronger build. historically.