Why I Downgraded from KMyMoney 5.2 to 5.1 - basics don't work

I guess you usually download the software executable file from the link #1 of the download page, don’t you?

Have you tried the other versions available under link #2 ?

I have installed under link#2 the kmymoney portable version on a windows 11 computer and I have no graphical issues at all. Everything works smooth.
Though, the installation steps are a bit more than a “classic” windows installation. If it helps, i wrote my step-by-step installation here: