Most people use a web-based email solution, but those are terrible at mass deletion. Take my advice and if you are looking to perform mass cleanup of those emails, use a client. It doesn’t matter if you use Outlook, Thunderbird, Astro, or any other email client out there if you set up a client you should be able to rapidly delete a ton of emails. I use the “Sort By Sender” feature to very quickly group email into batches which then allows me to very rapidly determine if these emails come from a source I care about. It’s a great way to unsubscribe as well. Once you’ve highlighted the offending emails, just delete and they will disappear from webmail as well  support the show: https://anchor.fm/60usefulseconds/support