SAML F5 as SP initiated with Azure MFA Integration

This is are the attributes F5 inserts and I do not see username or password as an option:

https://support.f5.com/csp/article/K23078281

Better try from the Azure AD side to fix things without the F5 Force authentication (this is just an attribute F5 SP sends to the IdP) enabled:

https://docs.microsoft.com/en-us/azure/active-directory/authentication/concepts-azure-multi-factor-authentication-prompts-session-lifetime

You can also test using F5 with Microsoft conditional access:

https://www.f5.com/company/blog/zero-trust-azure-active-directory-access-big-ip-apm

https://docs.microsoft.com/en-us/azure/active-directory/conditional-access/howto-conditional-access-session-lifetime