Group play dynamics are ruining the endgame for us.

As a disclaimer I'm enjoying the patch in general and like the changes that have been made, especially to crafting, but there are some aspects of group play which severely damage the experience.

I play SSF on a private league as a duo 90% of the time and there are several glaring issues:

Collision with players when sprinting and in general is ridiculous and annoying, particularly on maps with many narrow doorways and laser beam abyssals

The atlas passive tree map does not progress for both players in the group, on the rare occasions I play alone I have no atlas passive points because the quest to kill the eater of flesh isn't shared despite every other quest in the game working fine. This means if I play 10% of the time solo I am always having to play catch up but by definition I can literally never catch up.

The same is true for the king in the mists, Olroth, and the pinnacle bosses. Due to not playing solo I will never gain credit or atlas skill points for these achievements.

As far as I am aware boss kills have never functioned in this way throughout the entire life of poe1 and poe2. What has changed and why?