nix-dotfiles VS alacritty

You can check mine out. There are also some here

You can also try my full config: https://github.com/mjlbach/nix-dotfiles/blob/master/nixpkgs/configs/neovim/init.lua

I do, in fact, use expandtab

Here's my init.lua. Neovim nightly will read this by default if you place it at $HOME/.local/share/nvim/init.lua. I use this configuration on the neovim source (c/lua) with clangd and sumneko language server, and on projects for research (python mostly), amongst other things.

Not yet! w is window and o is options. You can check out my init.lua for most of the common ones.

For autocompletion, I recommend completion.nvim. Here is the pertinent part of my init.lua (uncomment require'completion'.on_attach()), but you can wrap this in a lua heredoc if you're still using an init.vim.

Which server? Here is a minimal init.lua and my personal init.lua

You're not actually using any of those channels. You need to overlay the channels onto your package set. If you hop on the IRC or discord we can work through your specific error message, but here is how I have it configured (with home-manager):

https://github.com/mjlbach/nix-dotfiles/blob/5f956f9548bdf7f9c954c926e6ab24e94c4bf55d/nixpkgs/configs/neovim/init.lua#L380-L425

https://github.com/zenixls2/alacritty this fork adds ligature support to alacritty

git clone https://github.com/zenixls2/alacritty

I believe it's this one, although I can see there's a new_ligature branch there which seems more up to date. The former is in the AUR as alacritty-ligatures-git.

I'm using this branch which supports ligatures.