I learned some interesting details about this a while ago from this video from Adam Ragusea on copper cookware, https://youtu.be/vZfvsaKrGss
From what I understand, pretty much the difference you'll notice with a copper mug is that it makes the Moscow Mule feel colder because copper conducts heat away from your hand faster than most other materials. A lining might slow down that conduction. OTOH better insulation will keep the drink cold longer.
I shifted away from Twitter to @kreynen a while ago, but I'm still a Fediverse/ActivityPub novice. I didn't know anything about Kbin and the community building tools in the Fediverse until the recent https://kbin.social/m/RedditMigration. I was already blown away before I looked at https://codeberg.org/Kbin/kbin-core. THIS IS A PHP/SYMFONY PROJECT! I'm not sure if actually shifting from Reddit to Kbin will be a viable option when Reddit corporate leadership eventually recognizes that enshittification is not going to be possible with this community, but I thought it was worth kicking KBin's tires and watch the service maintainers attempt to scale it. If these ActivityPub based communities take off, it might be worth running a Drupal Kbin instance to replace several corporately owned communities (Reddit, Slack, StackExchange, etc).