Update:
Today just to show the bug to someone else, I installed the update via Winget on a windows 10 PC and... nothing. It installed silently, didn't bother with asking a reboot nor crashed explorer.exe. So I went to another windows 11 PC and tried again with the silent updater and... silently updated without badly crashing explorer.
Either nextcloud fixed the installer for real or Microsoft fixed the reason explorer was crashing in the windows update that was pushed yesterday
Finally the days where all the explorer windows will disappear when updating NC desktop are gone?