I already wrote for the fact that I was able to order power banks and a power supply unit through my relative abroad and today he received them!! They are expected to arrive to me on January 16 (This is actually the best option that could have been because other stores said delivery times in several months 😨)

Bought two Baseus 100w 20000mAh power banks for $171
And a Baseus 100w power supply unit for $86 (Unfortunately, it turned out to be more expensive than I expected)

Thanks to everyone who helped me save up for this, it's actually a pretty big step towards my goal. The next step will be the selection and purchase of an LTE router!
And then, little by little, I will collect for myself on the iPad.