Luckygirl3 you could be my sister in law. Everything you describe about your mobility issues fits her situation perfectly, including the emergency alarm and the serious back injury last year. It is 5 years this week since my beloved brother, her DH, died suddenly.
I am actually in Tenerife with her at the moment, in a little quiet resort they visited twice per year for about 15 years. She wanted to visit one last time so I have come with her as it wouldn’t be manageable on her own. Now we are here she has very mixed feelings, it is obviously an emotional roller coaster for her. They had a restaurant they loved, but she will not visit it. I think what I am trying to say is be prepared to have mixed feelings if you do visit the place you loved together.
It sounds like your accommodation isn’t right for your current needs, had my SIL booked it I would have tried to talk her out of it because of the stairs. Your posts read like you have pretty much decided that you shouldn’t go, sometimes we just need to take the financial hit and move on. There is plenty more suitable holiday accommodation out there.