Multi Spam Email Blocking

We have email with our internet company. My husband has used this work email for years. We have it set up on our iPhones and MacBook pros in the Mail app that came on these devices. Apparently somebody put his email out there, maybe on the dark web. About 530 this past Friday evening he started receiving spam emails. It’s been exactly three days and as of now he has received over 12,000 (yes, you read that right!) spam emails. I spoke with our internet company and they said there’s nothing we can do to easily block them on their website. Is there any way on the Apple devices, using their Mail app that you can select multiple emails and block them all at once? We have been dealing with this and trying to block and delete emails for three days. Needless to say we’re fighting a losing battle and we’re desperate for help as to what we can do. I just feel it would be a huge help if we could select a bunch of them at once and click to block and delete with one click. If this doesn’t exist, Apple, please create this option!

FYI we are setting up a new email, but not with our current internet company. We will slowly be changing over.