"I want every single possible iteration of a skin" is a "Do nothing but play this game"-playstyle. 500kt is pretty cheap for a completionist goal tbh, if it's not obtainable for you, then change your goals to something obtainable. Buying all of the skins clearly isn't making you happy. Just buy the amount of skins you were buying before they increased it, or go modern-only, or make a list of your favourite species + pose and make your choices from there. There's a lot of solutions to this.