Okay, I run into this a lot. At least since PNPM.

Here's at least one thing that's worked for me:

Whatever the non-portable type is that it's complaining about (something imported from another library and re-exported)...

1. Create a named type alias for that type in the module
2. Export that type alias
3. Explicit cast the thing to that type alias

So

import { type Thing as LibThing, createThing } from 'a-library';

export type MyThing = LibThing;
export const myThing = createThing() as MyThing;

My understanding is you just need some concrete location for the relevant type to be referenced from that's exported from your own module.