It's not a default one, name is HiQDock. Though, it's not very usable. As there's no transparency supported, it takes screenshot of a background, so it might cause graphical glitches. The default dock (see the screen with Cave Story) is much better, works perfect
In order to figure out, what's Nix, how to use flakes and home manager, I'd recommend watching LibrePhoenix. It's absolutely fantastic guides. His repo with Nix config is also great, it's the one, which I'm gonna take as a reference
Please, give me some time, the repo is messy as hell now. If I were you, I would not do that now. I'm going to refactor the code, make it more modular in order to allow several WMs and themes. I'm also gonna introduce instructions for installing all of this)
However, the best way to enjoy system you use is configuring everything yourself, though it requires some time. In the past, when I copied configurations from unixporn posts, I always ended with dropping them and reconfiguring everything, as I like it)
Not really. I didn't really check how much space other snapshots, e.g. btrfs ones, takes, but now I deleted 630 generations (basically snapshots), and it resulted in freeing 11.5 Gb of space, not much IMO)
Revolt seems to be the best for now. Today they got a lot of money and I hope, they'll make their best to make it a reasonable discord alternative