After attempting to reset your Windows 10 v2004 (20H1) OS for whatever reason, are you hit with:
‘There was a problem when resetting your PC’
If so, there’s a workaround until MSFT fix the issue in this version:
Note: One critical thing they failed to mention in the article is the fact that you NEED to be connected online to do this 
1. Open an elevated command prompt. To do this, click Start, type Command Prompt or cmd in the Search box, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or a confirmation, type the password, or click Allow.
2. Type the following command, and then press Enter: dism /online /cleanup-image /restorehealth
3. Reboot your system, and attempt Reset this PC again.
source: Bleeping Computer
