Multiple factions are waiting for you to work with them in STALKER 2, and it all comes down to you being someone they view positively. You can make it easier to work with these factions if you increase your reputation, but how you do it is not entirely clear.
Although there are different and unique factions, working with them is straightforward. You have a choice to side with certain ones over others, which will be a repeating conflict you encounter throughout your playthrough. How you navigate these choices is up to you, but if you want to take a break from harming one side and increase your reputation, there are a few ways you can do that for every faction in STALKER 2.