404 Pages Not Found - Over 2000!

Hi Everyone,

New here so apologies if this is in the wrong section, we have a woocommerce website linked to our very large ebay shop (around 1200 products) through the official woo/ebay plugin.

We removed and deleted a lot of pages, as it was using far too much space on our server. Sadly though, this led to over 2,000 soft 404 pages! so the URLs are still there and load but the content on the page is empty and WP shows this:

Opps! The page you are looking for is missing for some reasons. Please come back to homepage

Our rankings have now taken a hit, any best practice we can follow, there are no suitable redirect pages we can send them too and there are far too many.

I don't mind google de-indexing them as i have no relevant page to send the pages too.

Thanks in advance!