Canada

How about instead we hire an oversight board and embed them in these companies to ensure they aren’t price fixing.

That would be communism! ™ (The Chinese commies do this in their large private corporations.)

But in all seriousness, it's definitely one solution. Another is creating a parallel public (state-owned) grocery supply and retail chain that operates at very low profit and letting these bastards compete with it. Both of those are significant market interventions though so ... I don't think the LPC would go for any of them. They've signalled that Competition Bureau is getting a boost to regulate from the outside. We'll see how much effect that has. In theory the CB can stomp the fuckers into submission if the gov't really wanted that but you know, the Liberal party tries to "balance" the workers' and business interests.