French fries are meant to be dipped. If they have shit dumped all over them, they are no longer fries, they are potato nachos. Which is delicious, but it’s not French fries.
For clarity: donair is a specific kind of doner kebab invented in Canada, not just a local name for it.
Canada still has other kinds of doner kebabs besides the donair.
I sort of consider dipping fries and fries with stuff on them to be two different but related species of meal, pretty much exactly like the difference between chips-and-salsa and nachos. Frychos.
As to preferences, for dipping, spicy ketchup (mix tomato ketchup 1-for-1 with siriacha or other hot sauce); for frychos, fucking everything! Load em up: guacamole, chilli, cheese, onions, peppers, bacon, mushrooms, gravy, salsa, mustard, marshmallows, spinkles, alright alright I’m getting carried away now, you get the idea!
In the UK most fish and chips shop vinegar isn’t malt but tastes just like it (most people don’t even know). You can buy the same stuff online or get it from wholesalers.