I have been having this issue for quite a long time now, so any suggestions welcome.

Actions that I perform in folders are not visible until I refresh the folder.

Let's say I am downloading a file, I click "new folder", nothing happens, I then have to hit F5 to refresh the current folder to see the one I just created.
I then have to refresh manually to see the file I just downloaded.

Same issue with thumbnails, I have to continuously refresh in order to get them to display, they seem to be getting re-generated every time as they display very slowly.

I was also having an issue with thumbnails simply not showing, but I recen

I have already done the following.
performed a chkdsk to fix any errors
done sfc/scannow
done DISM /Online /Cleanup-Image /RestoreHealth