How to completely remove number-named file folder?

After Direct upgrading Win10 to Win11 on my PC, a Wondows.old folder appeared in C:\. Today I compulsively deleted it using some tool but another folder named with a number emerged, which is tens of KB in size and contains thousands of subdirectories. I've deleted the number named folder with the same toole for many times, but it always emerges with a varying number each time.

Does anyone of you have idea to completely remove this folder? Thanks.