https://support.google.com/mail/thread/3011038/commands-to-delete-unread-emails-in-promotions-social-updates-deleted-even-read-primary-star-emails?hl=en

Here is one post about that:

"I was trying to delete unread emails from Promotions, Social and Updates category using the commands - category:Promotions,is:unread,older_than:6m. It deleted the emails I wanted BUT it also deleted all the read and star marked emails from my primary inbox, sent items and drafts. There seems to be a serious bug in these commands that it deleted emails which I didn't even want to delete. There were more than 10,000 emails in trash after this and I hadn't realised that all the important emails I didn't want to delete are also in Trash and I emptied the trash to free up memory. Now when I search all my important emails, I find none! Please help to recover these emails as the commands didn't work as expected."

Below that persons post are several answers.