Santorini Elevator??

I'm not sure the hotel is all you have to worry about. Much of the caldera area is nothing but steps and hills. The hotels I have been to on Santorini are built into the hillside where steps are critical for mobility and access. You might want to re-think Santorini.

March is off season. Most of the hotels and tavernas will not be open. Your choices will be very limited.

The Panorama Boutique Hotel in Fira has an elevator. I believe it's the only hotel with an elevator on Santorini.

And when we were there, the steep stairs down to our hotel did not have railings.

If Santorini is an absolute must, the most possible non-elevator hotel for her and you may be the Island's most Venerable one -- Atlantis, in Fira town. https://www.atlantishotel.gr It's been around for ? 75 years? and justly famous. Probably the most accessible, least walking required. Taxi can come right to entrance; 3 gentle steps up to lobby level... gently-graduated steps to room level. Right ON the scenic promenade of Fira for caldera view, right next to Cathedral & Museum, convenient to many restaurants & shops. I've recommended it to numerous people with bad knees/hips. It only has 25 rooms, but offseason, there's a chance to get one.

The big problem is -- it only operates April 1 - October. If you could change your date by a few weeks, it would be worth it. Otherwise I say, skip Santorini. You can't make something work, just by wishing.