What a nation says on paper isn't always evenly enforced. Where ROC really shines though is that it attracts a lot of american converts.
The issue with most lutheran denominations is ecclesiology. The state-church model and congregationalist model just doesn't work. Presbyterians proved this by staying conservative longer but ultimately the LCMS model is the strongest imo. It mimics congregationalism on ground level but ultimately runs itself like business that has very specific policies. The LCMS staying conservative and confessional proves that it isn't protestant doctrine that is the problem, its the typical forms of protestant ecclesiology, but when its done right it works.
I don't take the catholic church seriously for many reasons, namely because it CAN'T be the true church. It dogmatically affirms libertarian free will. It contradicts its own teachings and whores itself to other religions.
You can't lecture me about "valid clergy" when you are in a church that thinks muslims can be saved. There are already liberal denominations of lutheranism in the US, they operate fundamentally different from LCMS though. The LCMS literally hasn't budged, the catholic church is way more liberal and failed as a church than LCMS because your pope is a religious pluralist who sucks up to muslims and jews.
Also "confessional lutheran" isn't about "going to confession". It is confessional because it follows the lutheran doctrinal confessions, the confessions of faith outlined in the book of concord.