Agreed with @essicolo, if you are 100% stuck on using vscode this is a no-go.
[About kernels] Sorry, but as of right now this feature is only supported with Python. We are looking at supporting other languages in the future.
Yeah, that's the case for now, even if you start an external server. I hate having to say that, as we really want to support more of the various language kernels. But we started out with a Python focus and we still are pretty locked into that for the near future. Polyglot support is coming, but it won't be right away
per Microsoft Employee IanMatthewHuff
https://github.com/microsoft/vscode-python/issues/5109#issuecomment-480097310
preface - based on the phrasing of your question, I am making the assumption that you are trying to perform IRkernel
in-line execution from your text ide without having to use a jupyter notebook / jupyterlab.
That said, if you're willing to go to the dark side, there might be some alternatives:
- nteract's Hydrogen kernel for Atom IDE - the only text ide that I'm aware of that still supports execution against
IRkernel
. I know, I know - it's not vscode
but it's as close as you'll probably get for now.

- TwoSigma's Beaker notebook - it's been a lonngggg time for me but this a branch of jupyter that used to support polyglot editing, I'm not sure if that's still supported and it seems like you aren't that interested in notebooks anyway.