I would recommend looking into nvim-lspconfig for language servers mason for installing language servers and blink for autocompletion.

If you really want to use language servers via the running container, you probably install them in the image? You could then use a bind mount for the container to make them accessible locally and then prepend the location of the mount to the run time path like:

vim.opt.rtp:prepend(string.format("%s/lspconfig.lua", vim.fn.stdpath("data") .. "/lua"))

The later should work, but I have not tested that in any capacity.

Recommendation

Create a development container, bind mount the project into the container. Have your neovim config, and servers on the host.

Execute the code in the container.