Culture for code reviews doesn't start out of thin air. Unless you have processes for CI/CD, testing, task estimation, retrospectives, incident postmortems, etc., there's never going to be a point where you will convince people that they're helpful. So start with those.
There's always going to be pushback from adding more process, but if there's an understanding amongst the team that keeping things working is P0 then these processes will slowly/naturally come up as the team realizes that investing in them proactively will save them time down the road.
There's always going to be pushback from adding more process, but if there's an understanding amongst the team that keeping things working is P0 then these processes will slowly/naturally come up as the team realizes that investing in them proactively will save them time down the road.