how do i download itunes on a chromebook?

i have the ios 14 beta downloaded on my phone. it has messed my iphone 8+ up quite a bit. i also do not have enough storage to download the normal ios 14. so my plan was to back up my phone to my chromebook os, and delete some pictures from my phone so i would have storage to update my phone. my problem is that im not sure how to back up my pictures to my chromebook os. i tried downloading itunes but it says its for windows only. is there any possible way to download itunes on my chromebook?