The Filters option is great. I have to keep using ESC to navigate to my "send-to" folders, but that's OK once I figured that out.
What it can use, though, is an OR.
Example, trash emails "addressed" to Whoever in the World is That?" With an OR after the IF, the user delete anything not sent to any of multiple, personal emails. (Since, for instance I IMAP several accounts to my client, that's not an option as it now stands.)
Beyond that, I've been using Thunderbird for maybe 15+ years, & recommend it!
Patrick