I’m interested in buying an iPhone 11 without a data plan

Whether or not you can use an iPhone on any carrier’s network without a data plan is up to the carrier you initiate service with. Apple will sell you a full retail price, carrier unlocked device. But then it will be a condition of service with whatever carrier you choose for cellular service whether they require a data plan, or not, for smart phones.

You can buy an unlocked, SIM card free phone directly from Apple that would not be tied to a data plan.