A powerbank should always be carried in your hand luggage on the plane. In hand luggage, the powerbank is carried in the cabin and does not have to be registered. However, the instructions of the respective airline should be observed so that no problems arise in case of doubt. Here you will find a list of airlines with their dangerous goods regulations: https://powerbanktest.net/powerbank-...

in short, no. the 30000mAh at 12V are far too powerful.
see also: https://powerbanktest.net/powerbank-...

but I also had this with me, there are then the not so official limits.
The powerbank gets its own board card, is shown to the pilot on the way into the aircraft and if the pilot has no problem with it, you get the powerbank back....

so ask the airline directly...