There are two issues: probity and performance. PGMOL referees are effectively the regulatory bureaucrats here.
Here's how you fix the problem:
- Substantially increase the fixed income of referees at all levels. Just give them twice as much: compared to all this it'll cost a pittance.
- Define probity more clearly as far as income, asset and gift declarations. Ban referees from media or football consulting income.
- Enforce probity via audits, with punishment either by expulsion or "relegating" these guys back down the leagues for long periods where they will earn less.
- Mandatory rotation through match, linesman and VAR duty for referees at all levels.
- Relegate and promote 3 referees each season for each level, based on performance.
Put all that in place and I guarantee you'll have a platoon of excellent referees in place with personalities like dentists (no offence to any dentists) within three seasons. Get rid of all the ones who think they're part of the entertainment or have an eye out for every side hustle.