I don’t know if any other cars wheels would be better, when I bought my spare wheel I assumed the easiest way to get a perfect replacement was to source a GLA wheel so I didn’t look any further when I got one. As long as the stud spacing, central hole, rim width and offset measurements are correct then any cars wheel will fit, these measurements are available online for all cars but the thickness of the wheel metal would only be found by actually measuring the wheel.
Try
www.wheel-size.com for information on wheels, there you can enter your car and it will give wheel sizes and can tell you what other cars have the same wheels. According to that only the EQA and EQB have precisely the same wheels but you can get away with wheels having a slightly different offset (maybe up to 10mm, more than that could cause problems with clearances) if other dimensions are correct eg EQA offset is 53.5mm on a 7.5 wide 18inch diameter whee, Centre hole is 66.6mm, PCD is 5x112mm. GLA wheel is 53mm offset, other dimensions are the same.