Build your pizzeria website in Swansea
Swansea is not one market. It is a dozen neighbourhoods spread across three valleys and a seafront, and a customer chooses between pizzerias based entirely on which postcode they are in, not on price or quality. A site trying to rank for Swansea is competing with national brands for a search nobody makes.
Your customer is in your postcode
Someone in Mumbles is not comparing you to Morriston. They are comparing you to two other places that can get food to them in time. A site that names your neighbourhood, with specific delivery streets, honest times and a clear phone number, wins against anyone trying to rank for the whole city.
Mumbles, Uplands, Sketty and Monkwearmouth are not subcategories of Swansea. They are separate markets. Put the one you are in on your page title, on your Google listing and in the first paragraph, spelled identically, and have them link to each other.
Deliver only what you can make on time
Set your delivery zone to the streets you genuinely serve, with honest times. Everyone outside that sees collection instead of a late delivery and a one-star review. More orders, more predictable, more profitable.