some devices are like designed to work with specific voltage levels, so if your using a charger that has a really high voltage than norm, it could cause damage to your device , and also voltage affects chargins speeds
now both the wireless stands are QI2 enabled, which aims for higher effiency and power transfer, so it can support up to 15W or more.
And upon checking both have normal voltages
and both also have temperature control to prevent overheating
Finally though upon checking i can see the the satechi has a lower input voltage which means it would charge slower (it has an input voltage of 5V), and it would struggle to maintain effiency at higher power outputs, however the esr on the other hand has an input voltage of 9V which means faster charging speeds, its versatile beter at heat management cos it deliver the required power more better ,
SO take your pick
I do suggest you go for the Esr its the best choice according to your needs and it checks all your boxes, lol