If Nirvana Is Total Cessation, Why Do the Suttas Call It an “Element”?

In early Buddhist texts, there are instances when Nirvana is explicitly referred to as an “element” (nibbāna-dhātu) for instance in the Nibbānadhātusutta. Ud 8.1 likewise seems to refer to it as a sense object (ayatana) This terminology is confusing to me. If Nirvana is the cessation of all aggregates and not a conditioned phenomenon, calling it an “element” makes it sound like some kind of ultimate existent or metaphysical substrate. How should the term “element” (dhātu) be understood in this context. Is it meant in a strictly technical sense within early Buddhist thought, or is it more of a conventional designation for the cessation of processes rather than something that exists as a thing.