All-you-can-eat and à la carte are two markets. One is looking for quantity and price, the other for quality and a quiet table; promoted on the same page, you lose both.
Delivery is owned by the platforms and collection isn't. "Sushi takeaway" is searched in its own right, has little competition, and is the order that pays no commission.
Trust searches are a field of their own here: "is sushi safe", "sushi when pregnant", "vegetarian sushi". Answering them plainly gets you found by people who would never otherwise have ordered.
The lunch bento is a short-radius search almost nobody writes for. It's typed at midday by somebody with forty minutes, and the restaurant that has a page for it takes the order without competing on anything.