nix-dotfiles VS gruvbox

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/gruvbox-community/gruvbox is my favorite

i tried the more maintained fork of gruvbox and the original and i honestly don't know why how from keyword is highlighted in the original picture because I can only get it to highlight with treesitter installed and the following config:

But I find the colours are different compared to my usual https://github.com/gruvbox-community/gruvbox

gruvbox-community/gruvbox - My currently preferred color theme

gruvbox-community has a good support for main plugins like Lsp, cmp, gitsigns since treesitter highlight groups are aliases for other groups be default, you could consider it implemented somehow..