Not sure about the extra snapper images, but I used to have an extra "Garuda Linux on ...." (which was actually the same and only "main" one) caused by os-prober.
Can be worked around either disabling the prober or blacklisting the partition.
Let me see if I find it again, I found that on some Gentoo forum and posted here long ago.
edit: Duplicate Garuda linux boot entry - #2 by filo
No idea if this is the same problem though.
Er... see comment below.