check template, maybe there are an error,
you can add any string via custom HTTPD at admin level in (nginx_proxy) section, at any modification it will try to generate nginx_conf for selected domain from template, and will show are there any errors at bottom of this page
Why just not mount new disk as /home without any config changes?
rsync -av /home/ /hometemp
stop nginx/apache/ftp/email services
rsync -av /home/ /hometemp (again fast)
umount/remount/rename old /home
mount/remount/rename/ /hometemp as /home
also put new config to...
install IOTOP, use left/right arrows to move between columns and check what loads disks more, or you can use ATOP. I see that You have free 10Gb ram, so you can use it for caches to decrease disks load.
add/modify your mysql config, at [mysqld] section:
and restart mariadb
you may not install mysqltuner, just download script:
wget -o mysqltuner.pl mysqltuner.pl
chmod +x mysqltuner.pl
it may require mysql credentials in such case
./mysqltuner.pl -u da_admin -p
also about CPU: idle 382% - so You just using 18% from one core, all other...
What CPU they provide?
What type of virtualization?
what type of disks?
how much RAM? OS latest?
for me enough NGINX + PHP-FPM 7.4 + Opcache + mariadb 10.4 Recommended with InnoDB engine
with your Litespeed it must be faster. when you told VPN you mean VPS?
I think it's not hard to add additional credentials to config + NAME-field to describe server, and install another instances on separate ports or separate servers. So You will be able to use MariaDB, Mysql, Postgres etc. also it may be configured by custombuild like few PHP-versions (maybe...