Simplifying user login process on different tenants with different credentials
I have a scenario where "M365 is hosted on Tenant A with domain.com" and Azure AD for AAD Joined devices on "Tenant B with onmicrosoft.com" and on premises with "Domain.local" .
Problem-User need to login using different credentials in Azure AD joined devices and then Microsoft 365,issue is multiple logins as Azure AD for devices in one tenant with onmicrosoft.com and email /one drive and sharepoint/teams on office365 provider as domain.com.
AD connect is used between onmicrosoft.com to domain. Local and not domain.com.
Question-What different solutions available to simplify user login process or implement the SSO ,so that once user login with AAD joined device which is in tenant A they should be login without credentials into M365 which is hosted on tenant B.