Any offline IOS (or if needed android) maps software (vtt no subscription) for solo tabletop miniatures or game play?

For tabletop 1 inch grid maps, is there any map apps I can use on top of a large tablet (like the 13" ipad).

Then I can use tokens / minis on it (on a screen protector). Or if the map has built in tokens, I can use smaller than 1" and scale out and move the 'in app' tokens for it.

But something that is offline and no subscription (one time price is okay), something like roll20 but it doesnt have to be super advanced...just be able to make custom maps, so when traveling, so I don't need to connect to the internet (hotels or iffy connections etc.). Something like a VTT that I can just lay on a table and do some tabletop rpg games on top of (or if supports hex for some of the hex games).