Most likely PHP and MYSQL are already installed on your VPS as most of the hosts do install them by default. If you have a fully managed VPS then ask your host to do hardening i.e. installing and configuring firewall, modsecurity, ddosdeflate, rootkit checker etc.
I personally don’t do any installs/updates myself, even though I can easily follow instructions and do it myself as I do optimize the services after install, it is always best to leave it to the experts who do it day in and day out. Plus if something goes wrong, you can curse at others, rather than at yourself