How to contact an owner of a lost iPhone

I have found an iPhone 16pro in the river while diving.

iPhone works like a charm.

What I did to contact the previous owner:

1. went to the local police and said that this Iphone has been reported as stolen or lost (they didnt care much and said nobody has reported anything)
2. took the phone to iStyle (local Apple official dealership) staff told me that they cant track or contact previous owner.
3. called Croatian apple support. No help regarding the issue.
4.