Having corrupted drivers could potentially cause instability/crashes/BSODs. Not sure, if it could physically damage your GPU, but I never heard about it - in case of DDU! Yet drivers are complex. One NVIDA drivers even physically destroyed GPUs! So theoretically: maybe it could destroy your GPU. It is meant to be used before GPU switches, or if you have some serious problems! Don't use it, if you 100% don't have to!!!
I have RTX 3070 now, so I am scared to use it. I would rather reinstall Windows

I had one question: I wondered, if you should uninstall first drivers in control panel and then use DDU in safe mode. Or you can use DDU instantly? As it is not explained in tutorial. Ty!