Switch to trinity

Debian Buster, KDE 3.5.10. aptitude As more and more software-updates clash with their dependencies against what KDE needs or provides, I wanted to install trinity, preliminary stable, alongside KDE. KDE should stay operational till I had transferred my settings and programs aso to trinity. No go! Tdebase was fetched and seemingly installed, but when I restarted the computer and wanted to start KDE, there was only a black screen with the mouse-cursor and whatever I did with keyboard or mouse, nothing happened. Cold reboot to clear memory, same thing. Okay, let's then have a look at trinity. A blue screen with the logo appeared and after a few seconds something like "no ..... available check your installation"and I only could close that window via a warm reboot. KDE gave me the black screen again and also TDE said "check installation". Installed TDE again, same results as before. Half an afternoon had passed with no desktop still available. Glad, that I had backupped my system before the experiment and could restore my working KDE. So there's also a clash between TDE and KDE, incredible! Where should I look for the culprit for this disaster? Kind regards.