Simple solution
No-one should "own" any of it, it's a fixed size national resource. Have a highly regulated single infrastructure with no licence fee.
Have all the operators as resellers / retailers.
The Spectrum licence windfalls result in poor licence condition for performance and coverage and Regulatory capture.
It would be more efficient use too. Up to twice the capacity or more. Because if you chop it up between operators, statistically one in an area might have almost no users online and another operator at same location can be oversubscribed.
The current system is purely to benefit treasury and is a misuse of the idea of competition serving the consumer.