Do you really "fully understand the challenge associated with this or any product retirement. "? I don't think so. To even think that planner will support construction planning like MS Project / Project Online shows a complete lack of understanding of industry requirements.
Then I think, oh well, at least I can still go to Project Server Subscription Edition, but then I see that they are not supporting the OData reporting service.
https://learn.microsoft.com/en-au/project/deprecated-removed-features-project-server-subscription-edition#features-removed-in-project-server-subscription-edition
We are supposed to go back to the nineties and connect directly to the database for reporting. A lot of my clients don't even employ dba's anymore.
What a way to kill a fantastic product and replace it with a toy.