I've had my 2022 Bolt EUV Premier for almost four months and I'm getting conflicting information about my efficiency, but my car shows a number similar to yours (4.3 mi./kWh) over the 10,000-plus miles I've driven. The MyChevrolet app shows 3.8 mi./kWh though, so I'm not sure which one is closer to accurate. I've tried as best as I can to track my actual usage as well, but I'm just basing my home charging on the number of miles of range added back and doing the math as to how many kWh that equates to. Not super accurate.
I also tend to reset the trip odometer every time I charge up (usually only to 80-90%), and I've seen numbers as high as 6.0 mi./kWh on my regular drive (usually pretty free-flowing and maxing out at 55 mph). I do a lot of city driving too in Chicago and it's not unusual to still be in the area of 5.0 mi./kWh over the course of a night of driving downtown. It's only those pesky interstate trips that bring my average mi./kWh back down to reality ;-P
I wish there was a way to see actual kWh used and/or added over the course of time, such as with a lifetime count as well as maybe a "Trip A" and a "Trip B" like many ICE vehicles have. Does anyone else know how to address this?