we need an expert in linux/plesk/cpanel to fix the issues arises after migration of 4 websites

After a recent migration to Plesk, we are facing issues with four of our websites.

I need a Linux/Plesk/cPanel expert who can diagnose and fix the problems.

url will be shared after selection

1->Magento Website
after migration giving error:
There has been an error processing your request
SQLSTATE[HY000] [1045] Access denied for user 'admin_buhatalauser'@'localhost' (using password: YES)
Error log record number: 1691274313464

2->wrodpress website
giving following error after migration
Fatal error: Array and string offset access syntax with curly braces is no longer supported in /var/www/vhosts/vip-flags.com/httpdocs/wp-content/themes/porto/inc/functions/general.php on line 283
There has been a critical error on this website.

Learn more about troubleshooting WordPress.

3->Node JS website - after migration giving following error - error attached

4->one website running very slow