How to collect a sitemap from the results of the seo filter, without pages where the product is missing?

Question

Create a sitemap

Hello everyone, I have a task. Add links to all possible filter options in sitemap.xml. As a result, the client now wants those links that do not have products (these pages give a 404 error) not to fall into the sitemap. How to implement link checking? It came to my mind get_header , get the status, if 404 then throw it away. But there are about 170,000 filter combinations, it’s difficult to check all of them, it’s not fun to unload step by step, it will take a lot of time. How to make it so that only those pages where there is a product get into the sitemap, and those with a 404 error do not get there.

Answer 1

options:
1) walk through the router
2) take from the logs