There are no “real” alternative OS available for apple devices. You can get some IDE “lite” apps like Visual Code, Python Editor, etc. but these a meant as companions to a PC IDE not meant for compiling, linking, testing, etc. You might be able to trade the old iPad for an old laptop you can put a flavor of Linux on.
It’s half potassium chloride, that can cause you heart issues too if you get to much of it.