I'm seeing a few power banks on Amazon with "22.5 watts fast charging". That's not far short of 5A.
@pieist do you have a link?
Well, chosen almost at random from a search for "power bank 22.5w", this one, for example:
https://www.amazon.com/Anker-Foldable-Connector-Portable-Charger/dp/B0C6XK77HJ/
(I've had pretty good experiences with Anker. I have no idea if these will deliver that much current when talking to an SBC, or for that matter anything that isn't a phone designed to a particular spec. And then there's the question of "can it simultaneously charge and dischaarge, allowing it to act as a UPS?...)
Never mind, I'm seeing comments in forums to the effect that 22.5W is only delivered in a device-specific charging mode that uses a higher voltage. A Pi 5 will not activate that mode nor be able to use it.
Sorry for the misdirect.
@pieist Thanks. The max current at 5V for this charger is 3A
@makerbymistake
(Of course it's possible they won't provide that much current without some sort of negotiation that the SBC doesn't know how to do.)