The "Server" feature set should never be used and should be removed from the documentation. The valid two options are "ServerService" and "ServerNoService" depending on if mongod.exe should be installed as a service or not.
The installation tutorial for unattended windows installation: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-windows-unattended/#install-mdb-edition states:
To install specific MongoDB component sets, you can specify them in the ADDLOCAL argument using a comma-separated list including one or more of the following component sets:
with Server as the component that includes mongod.exe binary.
After downloading mongodb-win32-x86_64-2008plus-ssl-4.0.5-signed.msi, executing this via msiexec:
Resulting in missing mongod.exe in C:\Program Files\MongoDB\Server\4.0\bin