How long did you wait after you started the container?
It generates the ssl certificate on first run, so might be you didn't wait until the certificate was created.
It's not something we support, so it's on your own risk.
You have to follow the airsonic documentation and then figure out how to do it in a container.
You can't change the port to 1800 as the client looks for port 1900 as far as I know.
The only solution to having multiple DLNA servers on the same server is to set each container to its own IP.
Google nvidia nvdec matrix and check which cards support the codecs you need. Then you need to check if the card is support by the latest Linux driver.
Using the console entry in the menu takes you inside the container. Same as docker exec using SSH to unraid.
MariaDB has a built in client, but refer to the MariaDB documentation for how to use it.
It's probably caused by docker having its own IP range and sees your local network as remote.
There might be a settings file you can edit, but I do not know which or where. Might be better to ask jellyfin. Unless binhex knows.
Don't run commands to renew the certificate yourself.
Is your time and date in unraid correct?
You can trigger an update by simply adding a subdomain. After that, you can remove it.