FIx slow issue in the magento2 website -- 2

the website was hacked and was having bad script in the past and it was making big load when we open the the website we stopped the crone job and it was ok then we changed the theme for the website we got the japanes hacked so we upgrated the magento from 2.32 to 2.37 do we will not have to made all the upgrade to the extesions .......after the upgrade the japanese page gone but the server had very big load even when we disable the website the command was running so we made somthing today we installed new magento 2.37 and moved the database to it the load disappear but the website is very slow its loading on 8 to 12 sec

and before it was loading in 3 sec

we are having on the same server 2 other website and both the loading time increse to 6 to 8 sec

and they where faster than 3 sec 2,5 to 2,2 sec , other websites 2.44 with elastic search

now we are having error on the website like this


now the server need optimization

plus fixing the problem on the website ?

and check that we don't have Japanese hacking on the script or the server