Unflavored yoghurt has 5g of sugar (size of a sugar cube), and I’ve often seen up to 12g… (2 cubes and a half!) still branded as unflavored. It’s a crime we’re doing here, there is no place where we can get unsweetened matter.
The 5g per serving example is probably actually unsweetened, i.e. it's just the naturally present lactose. No sucrose.
We have "natural" joghurt in all stores (Germany) without any sugar. A breakfast with <1g of sugar is possible but requires some searching
No, but most yoghurt I see people buy are the sweetened kinds.
Buy unsweetened! If you can’t stand it, mix some pre-puréed fruit from baby jars intended for infants ($1 or less each).