I shall suggest you go for a Clean Install.
Visit:
https://support.microsoft.com/en-us/surface-recovery-image
Create Proper USB:
Download recovery image for Surface Pro 7+
Format USB → FAT32
Extract ZIP → copy all files to USB root
Insert USB
Hold Volume DOWN + Power
Release when Surface logo appears
Choose:
Troubleshoot → Recover from a drive
Select:
Fully clean the drive Reset or recover your Surface