How to temporarily disable all VSTs?

For a couple of months, I installed Cubase 10,5 then 11 on a brand new PC. Rather powerful PC with 16 cores, 128 GB, and all libraries and OS on nvme ( 5GB/s).
Before I used a Mac Pro, old one but powerful too, but unusable since 10,5 (weird display in Score Editor for instance).
Since I installed v11 updates Cubase doesn’t work properly: even in a project with just one audio track, no vst, no effect I get regular peaks in the Real Time Peak even if the single track is not played!
The 2 overload indicators are always red.
Windows 10 Pro is tweaked as far as I can to let Cubase do what it wants…
I tried all possible adjustments about buffers etc… my soundcard is a UFX+, I use the thunderbolt connection to get the most powerful gear… I don’t know what to do now.
Maybe, deactivate some VSTs…? Can you tell me please how to do this without uninstalling them?

start cubase and hold ctrl+alt+shift