It is the difference between nginx and apache: two pieces of software that do basically the same thing. With the exception of some naming conventions and UI differences, they are the same and both participate in the community in the same way.
If you go to Posts/All, you will see all the local communities plus all the communities subscribed to by the instance. I don’t foresee every instance mirroring the content of every community from every other instance - storage and bandwidth would go through the roof.
Communities that haven’t been subscribed to yet on an instance take a few minutes to show up after you search for them. This is something the need to fix: the delay is fine, but the need to provide useful user feedback, “connecting to community, check back in a few minutes”
Try this: https://browse.feddit.de/
I’ll agree that fetching a new community is much more awkward than it should be.
How many ports are on that charger? I have a group that plays D&D using a VTT even when playing in person. A 240 watt charger could power 3 or 4 laptops, greatly reducing cable clutter.