Thank you for posting this in Microsoft Q&A platform.
Keeping 2 different account with 2 different passwords for users while accessing 2 different tenants is always difficult.
You can surely make use of Cross-tenant synchronization feature in Azure AD.
Cross-tenant synchronization automates creating, updating, and deleting Microsoft Entra B2B collaboration users across tenants in an organization. It enables users to access applications and collaborate across tenants, while still allowing the organization to evolve.
Users continue to benefit from the security capabilities in Microsoft Entra ID, such as Microsoft Entra Conditional Access and cross-tenant access settings, and can be governed through features such as Microsoft Entra entitlement management.
With this user doesn't need to remember 2 different accounts with their passwords.
You can also check below article to know more about the cross tenant synchronizations.
Let me know if you have any further questions on this.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.