With a fresh installation on a windows 10 64 bit of libreoffice 7.2.2.
Everytime i try to open a previuously impress saved file, program seems to freez for 20 seconds, in task manager libreoffice seems freezed. After this time program start opening file. Problem appears only with Impress, not related to defender, to troubles during installation or tu resetting user profile.
In my case this was solved installing radeon driver from amd site (The cpu Ryzen 5 5600g has a graphic adapter inside).