Hi there,
SMTP is not deprecated at present in Windows Server 2022 since it's available as a regular feature in the servermanager and it's just working flawless (thank God for that!).
The problem with the MMC seems a security issue but you can simply edit the config file "C:\Windows\System32\inetsrv\Metabase.xml", and copy & paste content into the tag <IIsSmtpServer> from a working server (out of the very same Metabase.xml-file). One thing: change the value "FullyQualifiedDomainName" and save your changes.
Now reboot the 2022 server or the IIS Admin & SMTP service and you're set to go.
PS: When you've made a faulty change to the XML file, the service won't start. A file called "IIS Config_0000000000" is created in the same folder. With this file you can troubleshoot the error.
Cheers, Rolf.