It looks like they push an update every office day. I'm guessing if I installed 6 months ago and didn't update, that I should be fine?
Emphasis on guessing. If/when there is an actual postmortem, you’ll know when the back door was introduced.
You are either lucky or compromised.
Not updating air gapped systems is a security feature, not a bug.
I think VS Code extensions autoupdate by default, unless you disable it.