Bought a used iPhone — now it’s locked to someone else’s Apple ID

I recently bought a second-hand iPhone, and after performing a factory reset, I discovered that it is stuck on the Activation Lock screen and requires the previous owner’s Apple ID to continue setup. I do not have access to that Apple ID, and I am no longer able to contact the original owner, which means the phone cannot be used at all.

I have read that Apple may be able to remove Activation Lock if proof of ownership is provided, but I do not have an original Apple Store receipt. The only proof I have is the purchase conversation and listing from where I bought the phone.

At this point, I am trying to figure out whether there is any legitimate way to unlock this device, or if it is essentially unusable. If anyone has dealt with a similar situation or knows what options actually work, I would really appreciate the advice.