That’s been requested before, for AntennaPod: Keep X latest episodes.
I agree that’s a better solution.
There’s also an existing request for filtering episodes based on the tags (at which point you will be able to multi-select and remove from inbox): view episodes screen per tag · Issue #5222 · AntennaPod/AntennaPod · GitHub
As there are feature requests that will be better solutions to your use-case, I’ll set this one to resolved.
Thanks for having chipped in with your feedback!