Outside of having significantly more formats and methods available (some of which are experimental), the only other thing really notable is that 7zip doesn’t seem to have a “tar before” option, like PeaZip does. I can see that in the manual, that 7zip can tar files before compressing but you have to do that manually.
I should probably mention that my original comment was comparing PeaZIp to WinRAR. I actually didn’t use 7zip until I tested for the purpose of comparing it to PeaZip in this comment.
I do what I can to just ignore it. Sure, I don’t have a lot and my life is pretty shitty but I always remember that someone somewhere else probably has it significantly worse. Also, while I know it’s morbid to think like this, I know that if things get really bad, there will always be a way out.