We use this extension: https://marketplace.magento.com/sixtomartin-onelogin-module-saml2.html
The dev, Sixto Martin, is very responsive and helpful and it's been a 'hands off' extension since we configured it. We connect to an Azure AD and only use it to authenticate to the backend (admin site). It also supports front end authentication (store) but I have no experience with that.
You can configure SSO for Magento site using ADFS as an IdP using the below free extension. We also have premium plans for the extension which are rich with features including custom attribute mapping, role mapping, etc., and also have support for multi-store and multisite.
This extension is also compatible with the latest version of Magento 2.4.5
We also have a separate extension that is compatible with the SAML flow.
Please reach out to us at email@example.com with your requirements in detail and we can point you in the right direction.