There's an old adage: If you think auth is easy to write, you probably don't know auth.
I obviously don't know how much it compares to your specific case, but as general advice it's often good advice when phrased less antagonistically: don't roll it yourself because the rabbit hole is deeper than you expect.
On that front, you may think you are paranoid enough, but keep in mind that the service products sometimes have a multiplier effect in play: N developers of various levels of paranoia, M people in various ops/InfoSec/auditing roles, X committees/layers designed to minimize corporate security risk.
If auth isn't your job and isn't your core competency, many times it is worth asking if following the rabbit down the hole is worth the time you could save outsourcing to a multiplier effect of a team that focuses 100% on those tasks. As with most "buy versus build" discussions, it's not just about "comfort" but leveraging those multiplier effects. Can you pay someone else for the years of experience and "rabbit hole wandering" and multiple layers of security audits? Auth is a "must have" feature for most products but in and of itself is mostly a security liability and mostly pure overhead: no customer is paying you directly for your auth features, auth is the annoying hurdle to features that they do care about and will pay you for. All that time spent on auth and auth security audits rarely appear to provide good returns on investment for your product and your customers. Time spent on auth is time wasted from user-facing features.
I obviously don't know how much it compares to your specific case, but as general advice it's often good advice when phrased less antagonistically: don't roll it yourself because the rabbit hole is deeper than you expect.
On that front, you may think you are paranoid enough, but keep in mind that the service products sometimes have a multiplier effect in play: N developers of various levels of paranoia, M people in various ops/InfoSec/auditing roles, X committees/layers designed to minimize corporate security risk.
If auth isn't your job and isn't your core competency, many times it is worth asking if following the rabbit down the hole is worth the time you could save outsourcing to a multiplier effect of a team that focuses 100% on those tasks. As with most "buy versus build" discussions, it's not just about "comfort" but leveraging those multiplier effects. Can you pay someone else for the years of experience and "rabbit hole wandering" and multiple layers of security audits? Auth is a "must have" feature for most products but in and of itself is mostly a security liability and mostly pure overhead: no customer is paying you directly for your auth features, auth is the annoying hurdle to features that they do care about and will pay you for. All that time spent on auth and auth security audits rarely appear to provide good returns on investment for your product and your customers. Time spent on auth is time wasted from user-facing features.