I think when you say bosses you mean the actual aspirational "challenge" bosses. Not map bosses.
I have to be honest I dont think there is any place in this genre for mapping to be as long winded and tedious as the campaign is on a fresh start (after you've spent enough time actually getting upgrades). ~20 actual hours of mapping (not 20 hours into a new league, but actual time spent mapping) and you should reasonably be at the point where you can overpower map bosses. And yea, there should be a boss in every map, the current Atlas setup is not interesting or fun.
If you guys are saying that the pinnacle/uber/aspirational content bosses should be far more challenging, well I agree. That's kind of the point of that content and it should be optional and rewarding for the extra challenge.
The game is just not even close to balanced at all. Those bosses are actually challenging on many "normal" builds not using one of the overtuned interactions and I believe thats how it will be in the long run, with the caveat that PoE will always be a game where the ceiling is almost impossible to reach and players with enough time and currency will always be able to build characters that can 1 shot even the pinnacle bosses.
The difference between PoE1 and PoE2 at this point is it takes little to no effort, time or currency to be able to do that in PoE2 whereas it does in PoE1.