Howtoforge published a tutorial about installing Lighttpd with PHP-FPM and MySQL on Ubuntu 20.04 LTS.
How to Install Lighttpd with PHP-FPM and MySQL on Ubuntu 20.04 LTS
Lighttpd is an open-source web server that focused on simplicity and high performance. It's a light webserver with small and low memory consumption but still remaining standard-compliance, security, and flexibility. The Lighttpd web server is a part of the LLMP Stack, which stands for Linux, Lighttpd, MySQL/MariaDB, and PHP/PHP-FPM.
How to Install Lighttpd with PHP-FPM and MySQL on Ubuntu 20.04 LTS