https://unit.nginx.org/ is a "Universal Web App Server" brought to you by Nginx. For PHP support, it has a PHP module that creates PHP processes, similar(ish) to PHP-FPM, but without needing PHP-FPM.
It lets us get the latest PHP and install multiple versions of PHP on the same server (if so desired).
Then tell Unit to use this configuration to run the application: sudo curl -X PUT --data-binary @unit.json --unix-socket \ /var/run/control.unit.sock http://localhost/config/
First, we can't switch PHP versions without re-compiling the Unit PHP module.