I feel like this is something said by people who are more invested in VS Code than vim. The main vim plugin for VS Code is straight trash.* It's slow, buggy, and unintuitive; while lacking the extensibility that vim has. At least IDEAVim, which has the same limitations of being built in another IDE, replicates enough of the common plugins to be pleasant.
It's also worth noting that onivim is not VS Code repackaged. It is not an electron app, and it doesn't appear to use the monaco editor. They have apparently taken great design inspiration from VS Code, which I think is a fairly diffident decision.
Overall, I'm looking at neovim nightly and not knowing why onivim is a thing. I can understand the appeal of a GUI vim, but implementing a vim backend is a monumental task if you intend to be compatible with existing vim plugins (and you should). Nvim 0.5 has native lua, and now freed from vimscript the quality of plugins is improving continuously. I just can't see a way for a 'third vim' - if you don't start with vimscript you won't be compatible, but if you do you're already outdated.
* There are a few attempts to splice VS Code and neovim, all of these are awful.