RE: Help with API Endpoint change for a planned online migration
Without any further details, you might have to re-think some of these endpoints or refactor the logic. Today you might have a better option to do these mods and there might even be some standard functionality.
In general quite many clients and partners go for re-implementing the D365 applications and architect it from cloud point of view and not following the old on-prem design and architecture.
I am more than likely way to generic here, but my default preference on migrating from on-ðrem to cloud is not to upgrade but rather do a fresh implementation and leave the old stuff behind -> do a good house cleaning