Agreed this would be a useful function. I just installed Thunderbird last night and configured multiple accounts into a unified inbox. I accidentally swiped and deleted an email and looked for an undo button. Since there was none I had to go into each account's trash folder and try to find which email was deleted. Gmail and Outlook both have this option.
I can't agree more! This is one of the main features I miss coming from FairEmail which has this as well.
I admit I'm somewhat of a "lazy swiper" and you wouldn't think how often I accidently delete or archive a mail when just trying to pull down to refresh my inbox. And than I'd exactly as OP says - I've to go through all my mail accounts trying to find which mail I just deleted. And if it is an older mail that is nearly impossible because it isn't even at the top of my trash folder but could be everywhere.