I used to be able to delete multiple recordings at the same time... a feature that seems to be missing for me the past few weeks (probably since most recent update).
Current Server Version: 4.4.2.0
... with an Emby Premier subscription
Below is a screenshot where I selected all the episodes of a series. Clicking the three dots in upper-right corner I expect to see the option to "Delete" but all I see is:
Add to Collection
Add to Playlist
Download to...
Mark Played
Mark Unplayed
R