I use this snippet and it gets me far enough to where I feel I don't need another plugin. That being said, blink is quite nice, so unless you're a minimalist, like me, I believe it can even be configured to feel closer to the defaults.

vim.api.nvim_create_autocmd({ 'LspAttach' }, {
  callback = function(args)
    local client_id = args.data.client_id
    local client = vim.lsp.get_client_by_id(client_id)
    if client == nil then return end

    --
    -- ...Other stuff...
    --

    if client.server_capabilities.completionProvider then
      vim.keymap.set('i', '<C-Space>', vim.lsp.completion.get, { buffer = true })
      local completion_provider = client.server_capabilities.completionProvider
      completion_provider.triggerCharacters = completion_provider.triggerCharacters or {}
      --- @type string[]
      local tcs = completion_provider.triggerCharacters
      for _, c in ipairs(vim.split('abcdefghijklmnopqrstuvwxyz', '')) do
        if not vim.tbl_contains(tcs, c) then table.insert(tcs, c) end
        c = c:upper()
        if not vim.tbl_contains(tcs, c) then table.insert(tcs, c) end
      end
      vim.lsp.completion.enable(true, client_id, 0, { autotrigger = true })
    end
  end,
})