Two questions, and please don’t take it as criticism, I am just curious about rsync but also one point you make.
“They go unmaintained” seeing as Borg is in use for quite some time, how does this look safer for rsync? For me it looks like the risk for that is similar, but I might not know background of development for these.
Second question more something I am asking myself, a lot of people seem to use rsync for backing up, but it is not incremental backup, or is it? I saw some mention of a “time machine” like implementation of rsync, but then we are again at your argument it might go unmaintained as its a separate niche implementation, or does that main rsync support incremental backup? If not, are you not missing that, how do you deal with it when just a file changes? New copy of it being transferred or somehow else?