Vim's built-in packadd feature is available on Nvim too -- https://neovim.io/doc/user/repeat.html#packages ; and as long as there's a folder named 'lua' inside the package folder (e.g. $xdg_data_home/nvim/pack/the_package_name/start/), it's on lua's path/cpath as well.

One annoyance is making sure your lua modules can find luarocks you may have installed elsewhere. The easiest way to do that is to start nvim with an env LUA_{C,}PATH prefix pointing at the right folders.

The config examples for nvim plugins are just lua tables -- as long as the user has a clear idea as to how they're sourced alongside other stuff on the lua paths, it's not too big of a deal if the examples presuppose a particular manager. Lua isn't the prettiest language to read, though; and some of its syntactical 'shortcuts' can get annoying for people just starting out.