I don't know if the built-in Podcasts app does this, but Castro lets you tick a podcast subscription to be in "news mode". That way as soon as the new episode pops up, the previous one gets automatically deleted. It deletes a finished episode as soon as it does finish too. I like it mainly because it doesn't make you login to anything and it has a nice built-in search.
The data thing is hard. You could have 20 GB of it, but then you could also have three other people using it on the same plan, which is why I never really use it for anything other than browsing. Just this cycle so far my dad is using 3 GB, my brother 10 GB. I'm using 500 MB just from using Safari, Tapatalk, and the few apps that have to ping for weather updates, new email, etc.
I just grab photos in from Image Capture/iMazing to a folder on the Mac. I always am charging it on there anyway, so why not just do all that stuff then?