@Lina6208
Am sympathetic with your situation.
We have those amazing mini splits too, love them! They save a lot over central heat, by heating or cooling only the space they are in.
For me, this is one of those things about the hospitality business. To me, that means my guests' comfort and preferences have priority status. If my guests dream winter vacation is 86 degrees, that is what they are paying me to provide. Perhaps you might try a higher nightly rate for your place, and let the guests do their thing without stressing?