Please help...GSC coverage report issue.

Hey all,

I noticed that in GSC, pretty much everything tanked around May 16th The only thing I can see that correlates with that is the coverage report.

All my URLs said they were indexed but not included in the sitemap. (They are all valid)

I messaged support and got nothing, I switched from Yoast to All In One...Nothing.

I looked and made sure there's no manual actions and there was not a sudden drop in organic traffic, but it is slowly declining week over week. any advice on what to do?