I had my inbox filled, so I started creating rules

Emails from (let’s say) Google are to be sent to a folder called Google. When creating a rule, it asks you if you want to apply it to the inbox.

Check that, wait for a few minutes, and all Google emails will be inside the new folder. Once you start sorting you will notice that the amount of emails in your inbox reduces drastically.

I created rules that check the email contents for keywords. If it detects ads, then it goes straight to the bin.

Has worked for me for some years.