Ok another question - where do you see Cerby fitting into that mix?
All of these support oauth2 and SAML, and dynamic groups for less than the cost of each and okta (it seems to be the case everywhere I have seen okta used, another of the above providers is used additionally).
"Okta: comprehensive scim allowing your IT instead of random application admins throughout your company to manage user provisioning / deprovisioning. Start pages that don't require users to remember urls but instead show them a list of applications they can use. Adaptive MFA with IT-administered settings (though Google's super-enterprisey solutions may have sth here.)"
https://news.ycombinator.com/item?id=37995670
Personally, I just go with the Google Workspace and call it a day. Start page is one of those nice to have, but not required features in my book.