Apparently, the problem is related to a corrupted current user account. While there are ways to try to repair it, they are complex, unreliable, and rarely provide a complete solution. It's worth noting that reinstalling Windows using the Media Creation Tool you've already performed is, in fact, one of the most effective methods for fixing serious system issues, including the Microsoft Store. It preserves files and settings while reinstalling essential Windows components. The fact that the problem persists even after this process reinforces that the current user profile is corrupted to a level that even this procedure cannot resolve.
Therefore, the most effective and practical alternative is to start using the new user account as your primary account and migrate your data from the old one.
Transfer all files from the old user account folder to the new user account folder. User account folders are located in "C:\Users". There's no need to copy the "AppData" folder, as it often contains what caused the issue.
Once you're satisfied, you can remove the old user account by following the instructions under "Remove a user account" in the article I shared earlier.
No problem if you prefer to keep the old user until you're sure you've transferred everything.
Feel free to ask back any questions.