I managed to solve many unlogical hanjies, but this one is particulary stupid. And ugly, btw. For anyone interested, there are 4 pokemon-like balls: top left and bottom right on white background, top right and bottom left- black background. Somehow reversed.. somehow. Have fun, anyway.
I split it into 4 quarters, much easier that way. Each quarter is symmetrical. Started top right and bottom left. Top left and bottom right are exactly the same pattern but the black and white are reversed.
Thanks Bigweav1234 & Adevi for your hints - impossible otherwise!!!!
It really helped to start with the black underground ones :)