Dependency free microservice API docs aggregation/portal?

Is there a way to simply aggregate API docs from multiple sources (different microservices on different hosts) and show them in a single front-end, without having to inject a bunch of service registry nonsense into each individual app? Something like swagger-ui where you can select from a list of all configured services.

I imagine it as a kind of standalone API-docs server where you configure multiple sources, like sources: app1: https://foo.host:8080/api/openapidocs app2: https://bar.host:8080/api/openapidocs

And then I can run the API doc portal without these services knowing or caring about it. FWIW the services are written in Java/Spring. We do provide the API specification in OAS 3.0 in the services already.

I realize this can be done with Spring Cloud, but it requires a bunch of service registry stuff like Eureka etc that we don't want to bloat or environment with. The services are already running fine with service discovery etc handled elsewhere (mostly native kubernetes).