I haven't had to deal with this specific kind of use case before (accessing the local Jellyfin service while the laptop is connected to a VPN), but after some cursory research, one of these approaches may work for you:
Easy Option (only available on some VPN software):
There may be an option in your VPN client that lets you access local network addresses like your Jellyfin server. Check your settings and see if there are any options like "allow local network traffic" and then try opening up your Jellyfin server in a browser (e.g.: http://192.168.1.100:8096/)
Less Easy Option:
If your VPN client doesn't have an option for allowing local traffic, you can open up the command prompt on your macbook and run a command like this:
sudo route add -net 192.168.1.0/24 192.168.1.1
Where 192.168.1.0/24
is the local network you want to connect to (where the Jellyfin server is located), and 192.168.1.1
is your local gateway (probably your wifi router's address). Change both of these depending on how your network's local IPs are formatted.
This should update your routing table to handle local network addresses without the VPN and this should persist between reboots.
Hope this helps.
I'd say it's a somewhat different kind of interactivity than Lemmy. Your typical Mastodon user won't have many followers, but that doesn't mean you're "shouting into the void". Similar to Lemmy, you can comment on (reply to) others' posts and lots of other people can join in the discussion that way.
Not really, but you can follow hashtags for whatever topics you're interested in. Or follow an account for something you're interested in (e.g.: organizations, weather, hobby news, content creators, etc)
Follow people/organizations/tags that you find interesting and their posts will populate your feed.
Not necessarily. Reblogging ("boosting" on Mastodon) is just putting more eyes on someone else's post by sharing it; it isn't equivalent to an endorsement per se. You can favorite posts on Mastodon, but I don't think there's really an equivalent to a "like" or "upvote" button.
The range of content is as wide as anywhere else, memes and all. Can vary from instance to instance, though. (e.g.: code of conduct on mastodon.social may be different from fosstodon.org's)
I haven't used bluesky, so I can't comment on this one.