Demand to be called his/her/your majesty.
Whenever the trans-weirdos demand to be called plural pronouns like "they" it reminds of me Genesis 1:26's English translations using the plural pronouns for God: "Let us make man in our image.". Us Christians like to say it's a statement of God being a Trinity (which He is), but it's more of a statement of God being so majestic He deserves plural pronouns, especially for special occasions (like kings would sometimes refer to themselves on special occasions).
Maybe I'm too much of a Bible and history buff. But I find the demand to be called "they" about aristocratic.
That is the best way to deal with this BS. Agree to their pronouns as long as they agree to yours. I would insist on “My Lord and Savior”. See how it goes.