iPhone Locked to the owner

It's been 2/3 years since i had a problem with iphone SE (2020) model, that was used by my father which ended up with locked to the owner from forgotten password to the apple id and the number he used is also forgotten and the apple id is no longer in use. I have no idea how to unlock the phone and idk an services other than the company itself to unlock this. The only evidence i can give to this phones ownership is that my father got it from the work as a gift and dont have a receipt. Please help Apple.