Maybe not a doctor, but you need someone to test your hearing and write a custom frequency map for how your ear works. Good hearing aids are not simple amplifiers, they have complex signal processing to make it easier to hear what you want to hear (if you like music they make music worse, but you can understand the lyrics - this is a simplification, but good enough)

I just looked at the NHS site and they suggest your doc check your ears are not just bunged up with wax.

Beyond that I'm not sure why I'd need professionals rather than an app to do some hearing tests.