I think I solved the problem.
The reason is: In sites with high hits and many questions, tables such as "Tags" and "Discussion Views" are filtering on the homepage as they are linked to the "discussions" table.
Finds the question, pulls the tag from the "Tags" table with the help of "Api".
Then it brings "view_count". Look, for example, when you open the single question, you will not experience a decrease in performance.
But when you bring 20 questions together with their "api" on the main page, you will experience serious slowness.
I don't know how to overcome this problem, but normally flarum has a value of 400 500 TTFB, because of these 2 plugins, my values are now between 2-3k.