What I did.
a. Analysed all the possible issues. Hacking, technical, spam, breaching Google's rules.
b. Narrowed it down to content quality. Too repetitive, too obviously AI, not overly useful.
c. I redid all the content with my own AI solution so it was far better, niche leading.
d. I quickly also built some better content filtering/searching so users had an easier time using the site.
e. Decreased load times by 80%.
f. Redid the UX for the mobile site.