Typescript `atlassian-openapi` is not compatible with `openapi-types` OpenAPI3 type

[ThaDaVos]

I am using @apidevtools/swagger-parser to parse URLS to Javascript objects, after which I want to merge them using this library, sadly I am getting the following error in Typescript due an incompatibility:

I've got two questions:

1. How does one solve this?
2. Why is Atlassian's specific OpenAPI used here and not the global (as far as I could find, official) one?