There might be time you would like to relocate tempdb file to a new location.
Make sure the SQL Server service account has required permission to the destination folder.
Run the following command to move each database file to the new location:
ALTER DATABASE tempdb MODIFY FILE (name = tempdev, filename = 'E:\Temp\tempdb.mdf')
Restart SQL Server service and tempdb should be relocated to the new location.
If you encounter any issue that caused the SQL Server service fail to start, you can try to start the service in emergency mode and then connect to it make any required adjustment. Run the CMD in admin mode.
net stop mssql$sqldev_2019
net start mssql$sqldev_2019 /f
sqlcmd -S .\sqldev_2019
When you try to connect to the instance, you might receive error that “Server is in signle user mode. Only one administrator can connect at this time.”. Make sure no other service is auto start/connect to the SQL Server service. You may try restart the service again.