It is fair to point out he was following Washington's precedent in this. Also that the new Republic probably required some degree of ceremony to provide prestige to the new Presidency. After 12 years of implementation, relaxed manners were more feasible.
But Adams was an odd fish in many ways. Had the strangest ideas about the need for an American aristocracy and an upper house of Congress that would basically duplicate the British House of Lords.
“Your Excellency” was Adams’ idea, not Washington. When the simple sobriquet of “Mr. President” was suggested, Washington liked that.
Adams was indeed an odd duck. But he deserves much more credit than ever given. He was a doer, Jefferson a scribbler. Each has their place, but let’s not ever pretend Jefferson has been underrated.