File this under another iPad user has not bothered to make even a minimal effort to learn how to use their iPad. Over on Threads @mrnathansi writes
I have maxed out my storage on Apple iPad air, because Apple does not allow to offload files 🤔 What is the purpose of Cloud storage then?
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Of course this is easy to do and only requires the most minimal effort: In the Files app, long press (or two finger click with trackpad) a file that is stored in iCloud until you get the contextual menu. The very first item at the top of the menu is "Remove Download".