In addition to the price, Larryo should also define "lightweight" better.
"Lightweight" for an eBike in general is anything under about 55 lbs. Typical is 65 lbs, and they go up to 90-ish.
"Lightweight" in general bicycle terms might be under 25 lbs.

Also, how are you putting it in your Suburban? Do you have the back seats down, so it's a giant SUV, or are you trying to get something in with just the 3rd row down, or ?

I have a Lectric XP Lite, it was sold as 46 lbs. I added a folding lock, rack & fenders, so it's probably closer to 50. I wouldn't call it lightweight. Maybe 15 lbs. less than your Aventon?

I also have a Tern Vektron, which weighs about 50 lbs, which is "light for an eBike".

Aventon's Soltera is closer to 40 lbs., IIRC.

In the meantime, you might consider just buying a 2x12 to use as a ramp to roll the Aventon up into the Suburban.