Florence Hotels, yes again

Hotels in the $250 - $350 / night range in Florence early September are challenging.
When we added Florence to our itinerary I checked recommended favorites from the forum (Hotel Accademia, Hotel Davanzati, etc.) and was too late. I have searched the review section.
We need two rooms for four nights, one with two twins for twenty-something children and I need a good bed. I have a bad back and ended up spending most of last year’s Hawaii trip on the floor due to a soft/squishy bed. We don't need an apartment, but a/c is a must.
I booked a two-bedroom apartment at Florence Art Apartments from booking.com based on good reviews (can be cancelled with no fee up to a couple of days before check-in). There were only 162 reviews, which I understand is not a good sign. I have weird vibes about the place and cannot stop searching for something better. Don’t love the $350 security deposit, but I can’t find a review from a guest noting a problem getting it back.
I know at this late date my options are few. I see that Hotel La Scaletta still has rooms that might work but I don’t see a current review on the forum.
Any suggestions other than keep checking for a cancellation?
Thank you!