No experience with the CZ 600 and I don’t know anyone else who does.
Ruger Americans will shoot, but have crappy flexible stocks and are prone to small parts breakage, the feeding and magazines suck, and the actions are far from smooth. The aftermarket for upgrading them is pretty much non-existent. And if you could, you won’t get your money back out of it if you sell it. They are also more than $500.
Howa minis have issues with feeding from the magazines unless you swap the floorplate. The actions are also pretty rough (you can smooth them). The triggers can be improved significantly if you swap out the springs. You can get these for right at $500 but the factory stocks suck. The carbon stock versions have a decent Stocky’s stock, but are more expensive.
If you want to buy something for $500, plan on sinking some coin into it or dealing with issues. Going cheap is a caveat emptor situation. If you are going to spend $800 to a grand on a can, why put it on a POS that just annoys you?