I am at a medium sized company. We acquired a startup. They did not "live and die with automation", instead they contracted out the production operations. A dozen customers, all on snowflake systems which were constantly tweaked directly in prod with no documentation or audit process.
My experience on the acquirer side is that startup engineers like to just build stuff and deploy it. Design? Testing? Documentation? Automation? None of that existed in this company in any fashion. And they are themselves grating against a modicum of process. Please explain what you want to do, why, and provide a high level design. You are going to replace the whole auth system, it's not something you just "figure out" as you go along... Sigh.