I'm using a MacBook Air and was running into this same issue where I couldn't use the Export to PDF option despite having TeX installed. I tried several different fixes which included installing nbconvert (typing this into my VS Code terminal: pip install nbconvert OR conda install nbconvert) and mistune (pip install mistune) and then subsequently downgrading mistune (pip install mistune==2.0.0) which finally allowed me to use this code in my VSC terminal: jupyter nbconvert --to pdf "notebook.ipynb" (once I was in the folder of my .ipynb file).

However, this still didn't allow me to use the Export to PDF option which is so much simpler and quicker. The thing with exporting it to HTML and then print to save as PDF option is that it can cut off your code if a line is too long. What ended up resolving the issue for me was just uninstalling and reinstalling VS Code.