If anyone claims to be an enlightened being, whether a Buddha or an Arahant, they are likely deluded or lying to you. It took Siddhartha Gautama himself many lifetimes of selfless service before attaining Buddhahood.
If you were to meet an enlightened being, you would know by their conduct. They’d have no need to brag about it. Too many teachers have abused or taken advantage of their disciples while claiming an enlightened status.
As it says in the Lotus Sutra, “All Buddhas come into the world but rarely, and are hard to meet… And those who can hear this Dharma (from the mouth of a Buddha), such people too, are rare, like the udumbara flower.“