It occurred to me that the only way to disrupt the institution's ingrained, and effectively 'hereditary' racism, misogyny and broadly right wing culture, is to disrupt the organisation itself. Govts, especially recent Tory Govts, have not been above taking on large organisations..albeit opposing organisations, especially Trade Unions and whole industries. It can be done, but as you say it requires the political will, and it's clear that the Tories only will is to leave office having trousered as much loot as possible, which in turn requires a compliant, not to say corrupt Met.
Easy to say and probably very difficult to do, but I'd employ the equivalent of straining a tin of contaminated paint through a fine mesh into a clean container. Create a new Police Force with new leadership. Run it in parallel with the existing and staff it with both new recruits and applicants from the existing force via very stringent EXTERNAL vetting, finally closing down the old force.