gmail storage full - bulk deleting thousands of old emails

Do it on a computer, not the app. Search for before:2021/01/01 (any date you like) or older_than:3y, tick the select-all box at the top, and then click the link that appears saying "Select all conversations that match this search". That's the step people miss, without it you only get the first 50. Then delete, and go empty the Trash, otherwise it still counts against your storage for 30 days. With 60k it can take a few minutes to finish. If you want to keep the personal stuff, search category:promotions older_than:2y first, which gets most of the newsletters on its own.