A possible feature that I would want to see is to be able to have a single tab that would allow for filtering based on the platform, tag, individual, etc.
https://www.novelupdates.com/series-finder/ https://www.google.com/advanced_search
Where you can search all your subscriptions by meta data (and possible keyword in post).
An alternative but similar functionality would be a table where you can filter the columns. i.e columns might be Platform,Poster,Date,User Defined Tab[],Platform Tags,Summary
So for instance you can show all posts in between 20200219 and 20200305 not on twitter or youtube that are either your tech or finance tab that have the word covid or corona in the summary.
Great work by the way.