Waves Plugins cause Error Message

Currently I’m faced with a severe problem, I could’t find a solution in the online forums, but I still got hope that someone has had the same issues and maybe has a hint for me.
Spontaneously my Waves-Plugins started to cause error messages every time I try to load them in the Master section:

A severe error was caused by the plugin (/name of the plugin/). Wavelab still is running stable, but it is recommended to save your work and restart the program (translated from German)

I honestly am devastated and tried every trick from the book. Reinstalled all the Plugins, upgraded to the latest Waves Version v12, Wavelab Elements is running on the latest version 10.70, drivers for my RME Fireface UCX are up to date and my Windows 10 machine is running on the latest 21H1-Version as well.

My audio-system is top-notch, individually built with selected components and kept running like a charm for the last years. Never had a problem with it.

In Cubase the problem occurs as well, but with a different kind of behaviour. When I load projects no error message is displayed but insteat the insert-slots just stay empty.

Any kind of hint or tip is highly appreciated. Waves and Steinberg support has been contacted, but it make take a little while.

For the experts out there, some system details:

Prozessor: Intel(R) Core™ i7-6800K CPU @ 3.40GHz 3.40 GHz
Ram: 16,0 GB (15,8 GB verwendbar)
ID: 49E6F4C2-DA7F-43B2-84D3-CB8429E06A48
Produkt-ID: 00330-71325-04979-AAOEM
Systemtyp: 64-Bit-Betriebssystem, x64-basierter Prozessor

Edition: Windows 10 Pro
Version: 21H1
Installiert am: 16.‎04.‎2021
Betriebssystembuild: 19043.1052
Leistung: Windows Feature Experience Pack 120.2212.2020.0