RetroPie has the substantial advantage of having a real package manager underneath it. The same isn’t true of Batocera or Lakka. Having a real package manager makes it way easier to add things that might be useful.
Oh. Well, whether or not that truly matters depends on what it is you’re trying to emulate. Emulators that are still in progress are going to make the most difference for that. Emulators which are stable generally won’t.
In any case, thanks for the clarification.
As I mentioned (through an edit, so you might not have seen it), RetroPie has the massive advantage of having a real package manager behind it, something the other distributions you mentioned don’t have (I looked). So there can be significant reason to go with RetroPie even if it’s not completely up to date as regards some of the emulation.
The download link seems to be down, but there are multiple archives in the wayback machine, the latest one has the readme file which links to a google drive link that actually works!
EDIT: Yes i know that it is not recommended, but i’m having issues with mupen64 in both batocera and lakka where the screen is just black, so i’m going to try Retropie, maybe it will be better.