There are no truer churches. A church is one that preaches the true gospel, sovereign grace. Many people that are going to these so called false gospel churches are saved going to those churches, if God the Holy Spirit wakes them up while reading scripture that relate to saving faith. But they are not awakened by believing in a false gospel. If The Holy Spirit awakens them to the truth that they have been sinning against God their whole life and that Christ Jesus died on the cross to save sinners, that Christ took upon their sin debt and imputes His righteousness to them and they repent and believe and cry out to God for grace and mercy they will be saved. Once they are saved they will know they are in a false gospel church and will leave that church and look for a true gospel church, which are few now days.