Upgrading your organization from current versions to Exchange Server SE

So you need SA or cloud subscription license if u have free license for Hybrid servers that have no mailboxes and only used for SMTP to get Exchange Server updates?

Will Exchange Server SE include a free license for Hybrid servers?
Yes. As with previous versions, Exchange Server SE will continue to provide free licenses for qualified hybrid use via the Hybrid Configuration Wizard (HCW); however, unlike previous versions, you will need to either purchase SA for this license to get Exchange Server updates or have a cloud subscription license that satisfies the requirements. Please note that the Hybrid license is for the purposes of recipient management only. If you host mailboxes or need an Edge Transport server on-premises, you still need an Exchange Server license. See https://www.microsoft.com/en-us/microsoft-365/exchange/microsoft-exchange-licensing-faq-email-for-business. Also as with Exchange 2019, you will be able to use PowerShell and the https://learn.microsoft.com/exchange/manage-hybrid-exchange-recipients-with-management-tools without the need for a running Exchange Server, thereby obviating the need for any Hybrid licenses.