Hello there! Thanks for your suggestions, unfortunately they didn't help, I had to do a clean install again and this time it didn't help.   Then I did it again a third time, avoiding Dell's software and drivers (I just installed Windows Update drivers) and now everything seems to work fine again. Even the Thunderbolt 4 dock that I thought it was defective now works again.
Hello there, My Alienware 
 
   X17 r2 
  x17 R2 suddenly lost 90% of its performance in the last 3 days. It also can no longer recognize my TB4 dock. Opening File Explorer or applications is a pain.I tried to repair the OS and it failed, so I did a fresh clean install with the Microsoft Media Tool. Initially it was good, but after some updates it started behaving like a 15 years old PC again.Anyone else had this problem? I really can't identify from where the issue come?
x17 R2, super slow after July 24