The problem is the WiFi standard does not support SAML/OAUTH logins - which is the thing that Office 365 does support. To push this concept further, consider the case of accounts that don't use a password at all, such as FIDO2.
If you want a 100% Meraki solution and don't use an MDM, you can use Trusted Access (this requires a Systems Manager licence).
https://documentation.meraki.com/General_Administration/Cross-Platform_Content/Trusted_Access_for_Se...
If you are happy to use Meraki Systems Manager then you can configure that to use Entra ID authentication, and then have it automatically deploy a certificate to devices for future authentication. The feature is called "Sentry".
https://documentation.meraki.com/General_Administration/Cross-Platform_Content/Certificate-based_Wi-...
https://documentation.meraki.com/SM/Device_Enrollment/SM_Enrollment_Authentication#Azure_Active_Dire...
Some people use Entra ID LDAPS, although it is not supported by Microsoft. You have to build a VPN to Azure to make this work.
https://learn.microsoft.com/en-us/entra/identity/domain-services/tutorial-configure-ldaps
Some people have been playing with using Intune and Cloud PKI. This lets you deploy a certificate to every device and authenticate using that.
Some people are using scepman because it is cheaper.
https://www.scepman.com/
Some people use Splash Access.
https://www.splashaccess.com/portfolio/cisco-meraki-azure-active-directory-authenticated-wifi/