I think a variation on the multi community might be a good idea but implemented differently.

Community’s could opt into a meta community (somethings that are the same name arn’t the same thing).

Then on the user client side when you subscribe you can choose to subscribe to the meta community. When your feed is constructed it doesn’t include de-federated etc. when you post it is via your instance to the meta community and a shortcut is posted to all the meta community members, and replies go to your meta post in your instance.

A lot of people I know had fairly large DVD collections but never accumulated very many Blue-ray releases.

Even more so when you realize they aren’t even digital, they use analog NTSC, PAL signal modulation / encoding.

BlueRay came out in 2006, there are Teens that have probably never seen a CD or DVD.

Blockbuster died around 2010, apple stopped shipping optical drives in the last of their computers around 2013, Streaming became the norm, there might be teens that haven’t used “Discs” for video and have streamed everything.