You can't go directly into the cab as it seems you already know, thankfully. That's not a good thing to do
You would need to go into an amp and you'd want to go into the cleanest line-level input available (if any).
However, if you do go this route I'd suggest you disable any speakers/cabinets in AmpliTube or whatever amp sim you are using as you should normally send any amp sim software into a full range speaker. The software emulates the limited (in a good way) range and characteristics of speakers like those V30s already as if they were already recorded so you'd want to go full range. Or disable speakers/cabs in the software for better results.