This repo includes docker containers which I use.
To run aria2-rpc server you need to copy .env.example rename it to .env, change the secret value to whatever you want. Then by running docker-compose up -d it will start aria2-rpc on port 6890. You can change the port in docker-compose.yml. You can also run this container on windows by running docker-compose -f docker-compose.yml -f windows-compose.yml up -d.
If you are going to use torrent, make sure your ports are open, port ranges are: 6881:6999/udp. If you use UFW, you can use this command to allow those ports: ufw allow 6881:6999/udp