I have just received my iPhone 15 Pro in natural titanium and discovered an issue which is quite annoying when using the phone without a case:
The edge between the glass back and the titanium frame is not chamfered or rounded but very sharp, you can clearly feel it while holding it normally and you can also hear it when swiping across the edge with a fingernail. Right side is a bit sharper than the other.
Not an issue with my 14 Pro or 13 Pro.
//edit – Macro picture attached with edit.
View attachment 2275644