Depending on what you deem to be a suitable replacement i'd recommend:

  nvim-telescope/telescope.nvim // integrates well with code actions and searching (very extensible in general, similar to ctrl-p)
  hrsh7th/nvim-cmp
  hrsh7th/cmp-nvim-lsp // for language server completion
  neovim/nvim-lspconfig // a bunch of language server specific stuff

note, that you'll probably need a bit of time to configure it to your liking and that nvim doesn't install the language server by itself, so that is something that you need to take care of by yourself as well.

If you want to see what a preconfigured IDE-replacement might look like you can take a look at lunarvim(but beware, it misbehaves on windows quite a bit, you're better of with a linux system here)