VAN 1067 I'm getting desperate.

I have been struggling with this problem since May of this year. Without warning I get the error message VAN 1067. The special is only I play on Windows 10, TPM 2.0 and Secure Boot is both enabled (To prevent most Google responses to the error code). Unfortunately without success. Everything I do, even reinstalling the game, causes me to be able to play Valorant for exactly one day, or until the PC restarts. After that the error comes again. My walkthrough so far has always been to uninstall Valorant and Vanguard in the evening and reinstall it the next scheduled play before that. But slowly I don't want to do that anymore. The support wants to tell me since May to do a "Clean Restart". Not only does the whole thing not always work, it makes the PC feel like a Valorant Arcade because nothing else works. Now I'm hoping for some help from Reddit. Do you guys know this problem? Is there something that triggers this behavior? And what is the best thing I can do to make it stop?

Many thanks for your help. If you need info on my specs, feel free to let me know.