Okay, where are you going to get all the boats needed to export millions of gimmegrants back to homeland from? What if they have multiple homelands because an Algerian father reproduced with a Tunisian mother or god forbid a Frenchwoman? How do you plan on dealing with the governments of the shores you're dropping them at, since they don't want hundreds of thousands of gimmegrants on their shores? Do you plan on supplying the refugee camps with anything? If so, you've monumentally increased the scale of your operation, if not, why do you want them all to starve and if mass murder is your goal, why not just save money and build some "camps" with "delousing chambers?"
Yes, it's an incredibly radical operation that requires a huge amount of planning and resources, especially because unlike Hitler or Stalin, you aren't moving people by train to territories you control, you're moving them by ship to countries you don't control, and never will again without military operation since all those people you deported will take over the local government and stop exporting cheap shit like cotton and coffee. That's why the Germans never deported the Jews to Madagascar, because the logistics were simply insane.