JIGA 30000mAh Power Bank

The output voltage must be 5V minimum but when they advertise 30Amp it's for the 3.7V cells inside the battery.
When you convert that to 5V, it is equivalent to 22Amp hour.
(3.7 / 5) = 0.74
0.74 x 30 Amp = 22 Amp.
And that's considering 100% efficiency in converting 3.7V to 5V which never happens.
There is atleast 10% energy loss during the conversion, as heat.
So you're down to 20Amp in the best case scenario.
So at best this can supply 20Amp of 5V for 1 hour.

The correct unit to show the capacity of a battery is not mAmp hour or Amp hour
It's Watt hour.
Without knowing the voltage, the 30000 mAmp hour is just an advertisement trick.
Does this battery supply 30Amp of 5V over 1 hour or 9V over 1 hour?
Watt = Amp x Volt
So if this power bank can provide continous 9 volt 30 Amp for 1 hour, this is a 270 Watt hour battery. 270Wh
If the 30 Amp is for 5 volts, this is a 150Wh battery.
So, the 30000mAmp hour by itself doesn't mean anything. It's just a big number to make you feel good.

30000000 uamps. is 30000 mamps

Mine is 30000000 uamps.