I think the main problem is that we can have 30 armor class w/o buffs and 15 saving throws with advantage w/o buffs. I can achieve around 40-46 armor class with and every one have disadvantage aganst me with 50% dmg reduction.
I mean what they can do ... I gues nothing at least it feels like that. And again I play single class what is rated as worst class and the 3 least played.

Also on top of this we can use potions. And buffs.
But the enemy ist buffing they don't use potions.

About the enemy..
They have crapy armor class and savesI think the highest I saw was 20. And I am at lvl 12 and the enemy is 12 too.

My idea is to increase the armor class with +4 and +4 to saves also the monster enemys should use they potions and buffs.
I dont really felt that they are using healing or ressurection as well. So ai needs to be improved.