It looks like there is an issue with your Cache or Nucleus installation. On the image, it shows that Cache is off (The red icon at the top right of Isaac Sim window).
Try reinstalling Cache. You should be able to view your localhost files in Isaac Sim if both Cache and Nucleus is working.
That screenshot looks good. Cache is ON and you can access the localhost Nucleus.
It looks like there is already an Isaac folder on localhost. Maybe you can try delete the Isaac folder and try the download again?
Try running Isaac Sim with the -v or -vv flag to get more logging info.
If you would like to re-install Omniverse you can try the Cleanup tool here: Cleanup-Tool — Omniverse Launcher documentation