I love using my iPhone caseless but this exact same scenario happened to me.I always used a case and screen protector with all my iPhones, one day i decided to not use the case on my XS Max at the time and dropped it and the back shattered.
Didn’t have Apple Care and Apple wanted 800$ CAD to fix the back of the phone.
I've never cracked or broken an iPhone in my life (had them all since the original) and I decided to go caseless with a XS Max only to accidentally shatter the back glass on a hardwood floor when I picked up my coat from a chair and my iPhone was in one of the pockets.
Paying $600 to Apple was brutal and I wasn't too thrilled about it. At least I got a 'new' iPhone with a brand new battery and everything. Still... not very fun.