You can already do this by either editing the default filter for the list view or creating a new one which only shows done tasks (done = true).
Or create a saved filter for this entirely.
Great! Couly you elaborat a litle bit more on how to do this?
Being in a project’s list view and selcting Filter to the top right display the current filter { "s": "", "sortBy": null, "orderBy": null, "filter": "done = false", "filterIncludeNulls": false } in a modal and if I add done = true to the query, no tasks are shown in the list view.
I could probably change this default filter if I would run my own instance. However, I am a user of Vikunja Cloud.
To edit the filter for a view, click on the three dots next to the project title > Views > Click on the pen icon of the view you want to change the filter for > then in the form there’s a “Filter” input.