As Scott Schnoll mentioned at MEC 2022, Microsoft now supports Active Directory environments running on Windows Server 2022 beginning with Exchange Server 2013 CU23 and Exchange Server 2016 CU23.
It's interesting to note that Exchange 2013 CU23 does not support Windows Server 2019 Active Directory, so if you're running Windows Server 2016 AD or earlier you should plan accordingly. There are no issues upgrading AD directly from a previous version to 2022, bypassing 2019 AD.
The highest Active Directory forest functional level supported by all supported versions of Exchange Server is still Windows Server 2016.
View the Exchange Server supportability matrix | Microsoft Learn here.