Looking at the underside of the skate board that is Rivian I see the same kind of suspension that's been in use for years, specifically the Lincoln Continental, it sits on air bags and jacking it from the lower control arm with a standard floor jack is perfectly acceptable.
Since we can't compare apples to oranges eg: Rivian/Lincoln, Rivian/Tesla it's just my professional opinion. My training and experience as a professional auto tech tells me it should be very possible to raise a wheel by those control arms for things such as putting the spare on after a flat.
One would be SOL if they caught a flat and weren't on level enough ground to use an OEM jack, at least that's been my experience for the last 40 years that I've been buying vehicles of all brands.
Since Rivian is touting these vehicles as offroad specific, I would think they would be wise enough to include a simple floor jack for that purpose. Tesla's and Lincoln's are not built with offroad in mind.