The fact that we are even able to realistically compare a CPU in an ultralight laptop with no fan to an i9 is absolutely amazing. To me that would be an upgrade even if performance is a complete wash.
I think they're more light than ultralight. Otherwise the performance stands. LG Gram 2020: 2.07 lbs MacBook 2017: 2.03 lbs MacBook Air 2020: 2.8 lbs MacBook Pro 2020: 3.0 lbs
Also... I suspect benchmarking the LG or the 12" MacBook versus the Air would be pretty humiliating.