For the time being I switched to protols from buf_ls. It does offer Document Symbols view which is a step forward.

For LazyVim I enabled it like such:

  {
    "williamboman/mason.nvim",
    opts = function(_, opts)
      opts.ensure_installed = opts.ensure_installed or {}
      vim.list_extend(opts.ensure_installed, {
        -- other LSPs
        "protols", -- Protobuf support
      })
    end,
  },

and

 {
    "neovim/nvim-lspconfig",
     -- other stuff
         config = function()
           require("lspconfig").protols.setup({
           cmd = { "protols" },
           filetypes = { "proto" },
      })
    end,
}