phpMyAdmin can be installed in Ubuntu, Linux Mint and KDE neon via the package manager. But if you want the latest release, you can download a tar.gz archive from the official website and install the most current phpMyAdmin.
The web hosting provider webgo.de has set up an automatic installation of SSL certificates provided by Let's Encrypt within the web hosting space. There is no need to install any software. The SSL certificate is generated in the Webspace Admin with a few clicks.