Hi,
Alright, regarding the user cache, you can do the following: open the Command Prompt (as administrator) and run the command net user to see your username.
First of all, create a restore point:
https://learn.microsoft.com/en-us/answers/questions/3823042/discussion-how-to-create-a-system-restore-point-an
Go to Task Scheduler, select the task you created, and go to Properties > Security options > Change User or Group. Enter the username you found via the command and click "Check Names" to locate it; then click OK. Change the setting to "Run whether user is logged on or not."
Click OK; it will ask for the account password—specifically the Microsoft account password (the actual password, not the PIN). Enter it and click OK.
Apply the changes in Task Scheduler.
If that doesn't work, we can re-enter your Microsoft account password locally on your account to trigger a sync.
Thanks.