We certainly respect your decision to keep your system clean. Exactly for that matter, AppImages come into play, because they come as a single file which you don’t have to install and which does not mess around with your system. To get rid of it, you only need to remove the file. No uninstall or anything.
With that said, please be aware of the fact that the KMyMoney development team cannot provide nor maintain any other package format (deb, rpm, arch). We leave that to folks who know how to do that. And in case we talk about the KDE repo, we mean the source code repository.
The last commit to the stable branch is the following:
commit eef04f1e9dc9f765ec74320008f095870e16a537
Date: Fri May 3 18:30:48 2024 +0200
Avoid violation of the C++ One Definition Rule
BUG: 486486
FIXED-IN: 5.1.4
which matches the version you reference. The Help/About KMyMoney dialog should show the above commit hash in the version number (truncated at some point)