Cars aren’t freedom though. You can only go to places where there are roads/streets and you’re entirely dependent on energy logistics to provide you transportation. You’re entirely subject to a delayed schedule through traffic (accidents/congestion).
If you also bring your car to a public parking area, you can subject yourself to potential theft.
Of course living in a city where space is at a premium you’re going to be limited in living space but there’s nothing stopping us from Building out public transportation and alternative methods of transportation out in to suburbs.
Since you didn’t quite get an answer, an “instance” is like a “website” kind of. Just like you’d go to Reddit and have access to all of the subreddits on their servers, an instance is a one version of Reddit. There are multiple “Reddits” like lemmy.world, lemm.ee, feddit.de, etc that all have their own “subreddits”. They all interact with each other though so you can see every community on every instance as long as they’re still linked.