Ask HN: How does your dev team agree upon code standards for your repo?

At my last gig, on a team of about 30 devs, we had long email threads debating code issues: following patterns correctly, introducing new patterns etc

The threads often fizzled out, didn't reach agreement and those that did, did not translate into the dev team actually following the newly agreed (or newly reemphasised) patterns.

I've heard other teams have scheduled meetings to discuss general code hygiene (tech debt, inconsistent standards across the codebase etc), others simply discuss them as they hit them in PRs and slack. I'm wondering:

1. What processes, techniques and tools are teams using out there and 2. Is the lack of a structured process from identifying/proposing a code standard/rule through to discussing/refining/getting buy-in with the team and then ensuring it's actually followed a commonly felt pain?