Agreed with Mohit.
Also please try with CE ( Community Edition, not docker ) first, that's easier to find out if SAML SSO working or not. CN ( Cloud native ) / Docker / K8s has bunch of network related sides which might require some tweaking.
Please test with CE first, have an idea how SAML SSO works with Gluu Server, do same for CN ( Cloud Native ), compare your config with CE. You will know what's wrong where.