How to use the metadata type in a custom type?

Question

export default {
    types: {
        VCRequested: {
            xxx: "xxx",
            assertion: "Assertion",
        },
        Assertion: {
            xxxx: "xxx"
        }
    }
}

As shown in the above code, Assertion is my custom type, but there is a CorePrimitiveAssertion type within metadata that is identical to Assertion. I want to directly replace it with CorePrimitiveAssertion, but when generating types, I get an error:

build/interfaces/vc/types.ts:266:25 - error TS2304: Cannot find name 'CorePrimitiveAssertion'.

266     readonly assertion: CorePrimitiveAssertion;
                            ~~~~~~~~~~~~~~~~~~~~~~

It seems that CorePrimitiveAssertion is not automatically imported into the generated types.If I manually import the following code in this file, it all works:

import type { CorePrimitivesAssertion } from '@polkadot/types/lookup';

All other types work fine. I just want to replace an existing type in metadata within a custom type. Is this achievable?

Version: "@polkadot/api": "^10.9.1"