Ubuntu unity made it easy to access recently used files by clicking on the dash button and type some characters of a recently used file. The activities overview in Ubuntu 20.04 works similar. But it does not show any results - instead a file search is triggered (taking a long time and usually without results).
Since Ubuntu can track my activities (https://help.ubuntu.com/stable/ubuntu-help/privacy-history-recent-off.html.en) I suppose there a possibility to show these files in activities overview.
An older Ask Ubuntu thread posed a similar question, but is completely outdated: No recent files in GNOME Shell
I did not find any working gnome-extensions that can add this feature. My only solution so far has been to install an external launcher (Synapse).
