You didn’t mention the vehicle mileage or how long the plugs had been installed.
Considering by your description concerning the oil usage.
Is there excessive blue smoke from the exhaust?
You may want to do a compression test to see the state if each cylinder.
Next do a leak down test to note if you have any issues.
If the engine passes both tests and reads with in spec.
You may have issue with valve guide seals leaking or clogged oil rings