Say getting a base ammount per problem fixed or identified to some standard say $20k for solving severe stomach ulcers with bonuses for things like not having any longterm damage, minimal patient suffering and such. It doesn't matter if they use cheap antibiotics or surgery or how many screening tests were performed in that hypothetical.

Granted there would be major devils in the details especially if it causes "underwater" patients.

Except not every patient can be fixed. Doctors would be incentivized not to take on really sick patients or those with mystery illnesses.

That's exactly what would happen. In a university hospital setting it's the most experienced physician that takes on the most difficult cases.