If you’ve lost control of your inbox, a good way to deal with it is to sort by ‘From’. This will group together emails based on who sent them:
It’s generally much quicker to work through emails from a single person to make sure you’ve not missed anything, and if you are confident there’s nothing outstanding you can click their name at the top to ‘select all’ and immediately archive / delete their emails:
Inbox zero is in sight at last!