I have to thank you as well! I tried and failed to deploy from their instructions a few times but I don’t think I realized how hard coded the db info was. Glad I could give something back. Cheers!
The problem is that the invidious container is trying to connect via a dns name (i.e postgres.) By design bro or bridge networks don't have container to container dns. when you create a custom network (i.e proxynet) it enables DNS for that network, there for adding both invidious and postgres to the custom network is why this works for Joshndroid.