VSCode has a similar approach, they use ⌘ K as the leader prefix, follows another one or two keys to trigger a command, for example, the default keybinding for “Fold all” is ⌘ K, ⌘ 0
Try searching the forum for “vimrc”. I am pretty sure some people found a way to customize some of it. (I never did.)
And just keep this context in mind: the Vim bindings are provided through that CodeMirror project I linked to. If you google things, that will be important.
No, the Vim bindings are not a real implementation of Vim, let alone an implementation of Neovim. Maybe it’s possible to do something like that with the API, but I wouldn’t expect Obsidian support for that.