That is not at all true.
"Qi chargers" are not all the same - for example stand-type Qi chargers almost always fail to work with new iPhones because they hold the phone in a certain relationship to the charger's Qi coil, and the position of the coil changes between models; by comparison, puck-type Qi chargers usually work with all phones.
So a great example is I have stands from Logitech and Belkin that worked with my iPhone 11 Pro Max but don't work properly with my 12 Pro Max:
Belkin for one openly states that it is not compatible with the iPhone 12 family - but they are coming out with a new stand that will be.
Your NANAMI docks are another great example - they hold the phone in a precise relationship with their charging coils, and the coils in the iPhone 12 phones aren't in the same place they were on previous iPhones; the position of the coil in the phone is not part of the Qi standard.
On the other hand, I have a Mophie Qi puck that I bought for use with my iPhone X that still works perfectly to charge my iPhone 12 Pro Max:
I have MagSafe chargers as well, and I prefer them for their additional functionality but don't have to use them.