I have a faction idea:

There should be a faction that rewards collaboration like how Arachne rewards finishers and looting. It could be one of the existing factions (but who) or a brand new one.

Maybe players forming a truce will give some rep points for this faction and disables damage between their crews (in order to prevent people from farming both this faction and Arachne, but I can see how it can be problematic) and some rep points for sharing exfil points or using Mercy Kits (like the CARRI "event").

It gives players a choice; forces them to choose between allyship or loot.

PS: This also kind of solves the teaming in Cryo. Instead of it being in a grey area, it's now a legitimate tool that any group of players can make use of.