After being hacked by the Chinese, the site on Wordpress slows down. Where to dig?

Question

Burglary protection

On the site, while it was being made, there was a light password like test. Accordingly, at some point, the Chinese rolled it up and filled it with Chinese doras. The first symptom of this was that the site began to slow down (not only the site itself, but also the admin panel). I cleaned the root, removed the dora. The brakes didn't work.
Now I checked it with an i-bolit: LOGS It
seems that there is nothing suspicious. Moreover, if I change the current Wordpress theme to another one, then the site starts working quickly.
Where to dig? Who will tell?
Patient:100matika.ru

Answer 1

Carefully check the theme files (in the left editor, paying attention to the length of the lines). Update WordPress (let it replace some of the files, you never know what they could have left "as a keepsake"). Delete all cache, including theme cache.