Guilt and the after effects of such are quite literally bound to the human condition. Richtofen the Primis version anyway dosen’t strike me as being an evil man at all, unlike his Ultimis counterpart. He actively does what he does for the safety of the multiverse even if he has to step on a neck or two to do it. Does his crew hate him? A few of the members, yeah sure. Dosen’t stop him from fighting to save all universes from being eaten by the Apothicons though.
After all he is “the nicest one and you will never even know” in his own words. So if he was forced to do something awful/evil to someone who is a good person or do something morally repugnant for the greater good would he feel remorse and guilt over doing so? He isn’t a sociopath just more grey than most people is all. In my eyes anyway. Then again he couldn’t come up with a difference between him and Ultimis in alpha omega so…