My 2 cents - don't rule out EQS if you like it.
Yes, Gravity looks like a better deal on paper (power, range, cargo capacity), but (i) unclear if everything that was promised will actually be delivered (real world range, software, interior quality, any issues down the road), while EQS has been around and you pretty much know what you get, and (ii) EQS is likely a better deal as MB dealers have a ton of EQ incentives, so MSRP is irrelevant.
I drove EQS 580 sedan for 2 years, great car - quick, efficient, great range with very minimal losses if you go above 85mph or drive in extreme heat. Had zero technical issues with it.
Test drove Air while I owned EQS Sedan - was not impressed, the car is nice but it's much smaller (it's more of a E-class / 5-series competitor) with unusable back row due to very high floor (unless you go with a small battery), and the software was meh - laggy, poor camera quality. Trunk is also on smaller side with a small opening. I brought a 7ft Christmas tree inside of my EQS sedan with no issues.
I was looking forward to getting a Gravity and had a pre-order, but as (i) there were no major updates on deliveries and my existing lease was expiring soon, (ii) there was a risk that EV credits / incentives might disappear with a new administration, I traded for EQS Maybach SUV - got a good deal, and cancelled my Gravity order.
Gravity might be better than EQS in some aspects, but EQS will likely win some points too in a face-off. All I'm saying is if you / your wife love EQS - feel free to go for it, it's a great car!