I have trouble thinking of kasha as anything but kasha. I thought that kasha is like a universally accepted concept, like how we just translate hryvnia into hryvnia.

"Hot cereal" should be accepted in place of porridge. I never once used porridge growing up except when telling "Goldilocks and the Three Bears" nor did i know what it means until i just recently looked it up.

I didn't even know that English had a word for anything resembling каша, попара (porridge with bread), помажда (porridge with semi-crushed wheat, in Bulgarian called трици), качамак (with maize flour) and other of this sort. The only time I showed what this is to a British friend of mine, he said it looks like "pig's food" so I thought British/American cuisine doesn't include каша-type dishes.

I wrote "Do you have a porridge with butter", it wasn't accepted.

Ukrainians call lots of things каша. Buckwheat as well as porridge oats (or as the Scots call it porage)