For SAML in particular I can definitely relate here. I will say though, that for SaaS products that you want large companies to use, you owe it to yourself to have an auth layer that is immensely flexible and pluggable. Auth is a huge mess and large companies nearly all have single-sign-on solutions, sometimes strange bespoke ones, and so you gotta expect to potentially build a zillion different auth integrations if you want to sell to large companies.