If you search here, you'll find years of posts about problems with the Aperture/iPhoto importer plugin: greyed out buttons, unusably slow for libraries larger than a few thousand photos, stalling on "poison" photos, other bugs. The plugin was poorly implemented and Adobe has never provided support.
The old manual method works best with a working Aperture, which you don't have:
Consider getting the Avalanche app, which many have reported works very well (and it preserves your Aperture edits as LR Develop settings). Avalanche for Lightroom current costs $59, but I see they've just introduced a $9.99 monthly subscription -- perhaps you can just pay for one or two months and be done. Regardless, how much do you value those old photos and your time?
Interesting, and Avalanche looks as if they have resolved quite a few issues. Their other software, (PEAKTO) you can trial before purchase but not Avalanche, so I might only find out it doesn't work on Ventura until "after the fact". Perhaps the monthly option and "get it done" is the way forward.
Thanks for the steer, It didn't show up on any of my searches - not quite sure why - but it looks like a very good option if it is "Ventura friendly."