Hey, so over here a prominent developerr says he always uses the latest Node LTS in his development version, suggesting that there should be no problem with that.
So that means hyour Node issue should be totally safe.
It seems highly improbable that libcurl would break things in a non-backward compatible way, so maybe your task isn’t as hard as I’d imagined. So, maybe just 1-5 hours work for someone familiar with the various pieces.
So I think you’d just need to fork discourse_docker and change a few lines in slim.Dockerfile and maybe it’ll just work and not be a big deal after all.