Tarah Wheeler5-person company about to hire more and we're on M365:
Okta or Duo?
[If you say Azure AD FS, I'll make you read the eight-year-old docs for it til you get galaxy brain]
Simple Nomad@Tarah If you need integration into a lot of different SaaS providers or something, Okta. If not and you will stay fairly small, maybe Duo.
BTW Duo for Unix (for my Linux servers) is wonderful, I use that on my home systems.