Don I am intrigued by the phrase “I read somewhere”!
Brassicas do reduce the damage from white rot, if it is present, so growing them before garlic has its uses.
I am not a fan of strict rotations and if someone eats a lot of brassicas, your description makes sense. If not, you could grow beetroot, carrots, salads etc after the garlic.
I think it depends what you like to eat more than anything.
