Adding this to NeoVIMs lazy plugin called hrsh7th/nvim-cmp solves the issue, while not being on the most recent version. Basically setting the version manually.
You might have to

1. add this code to init.lua plugin section:

<other plugins>
{
  "hrsh7th/nvim-cmp",
  commit = "b356f2c",
  pin = true,
}

2. remove the plugin from the plugins folder manually (to make sure the other version does not keep existing. In my case this is in ~/.local/share/nvim/lazy/nvim-cmp

3. Remove nvim-cmp from the lazy-lock.json which resides next to your init.lua file.

4. Now you can reopen nvim and watch it install the defined version. (and enjoy the pleasure of an error-free-coding-bliss again.)

5. if this did not work, you can do it manually by going into ~/.local/share/nvim/lazy/nvim-cmp and type git checkout b356f2c to switch to this specific branch yourself.

*Good to know: This is basically the same thing that neovim would do for you. You'll see the already pre-existing git repost if you type git status in one of the plugin folders.

Credits:* https://github.com/hrsh7th/nvim-cmp/issues/1877