what am i doing wrong when i cancel hulu?

for apple it's settings, tap your name, subscriptions. google play is in the play store under payments and subscriptions. you keep access until the end of what you've already paid for, so it still working tomorrow doesn't mean it failed.

You can't cancel from the TV app - it has no billing section at all, which is why you can find everything except the one button you want. It has to be done in Account from a browser or phone. The bigger thing to check first is who actually takes the money: if you signed up through Apple, Google Play, Amazon or inside a Disney bundle, cancelling on the Hulu side does nothing and you have to stop it where you bought it.