Common scalar and enums across subgraphs

Hi guys I’m in the process of thinking how to migrate my http monolith to a federation approach and one problem I’m facing in the desing is that I’ll need to use the same custom scalars and enums across different subgraphs.

I’m wondering if there is a pattern or technique to manage this as if in the future I want to change a scalar or enum I’ll have to modify several subgraphs at the same time which doesn´t seem reasonable.

I don’t know if one solution could be to declare them all at gateway level to be resolved there or maybe having a subgraph exclusively for resolving custom scalars and enums?

Thank you!