I created an installer script for Gitea to simplify the installation on the Debian Buster. There are only three simple command to run as root:
wget https://raw.githubusercontent.com/emrahcom/emrah-buster-base/master/installer/eb
wget https://raw.githubusercontent.com/emrahcom/emrah-buster-templates/master/installer/eb-gitea.conf
bash eb eb-gitea
Please see my Github page for the details: