Samesite Cookie Session Problem

Hi there,
I have a technical problem with Vaadin 24 and hope that you can help me with this, since I have already tried a few things. Specifically, I have developed an application with Vaadin and want to embed it in an external website. It is hosted on another server.

Unfortunately, I always run into the same problem when calling it with a Safari browser (macOS, iOS, iPadOS): a red message comes up, saying that Cross site embedding cookies does not work. If I allow cross site tracking in Safari settings, the object loads.

I tried to solve the problem server-side, but got no result here (keyword content policy). The type of integration (Object, Emdeded, iFrame) and possibly changes in the header did not make a difference either.

A colleague also tried various things (also following the official Vaadin help post) and here more questions came up:

In Vaadin, the session ID is stored in the cookie. I tried in Spring Boot to set SessionCreationPolicy.NEVER for certain requests, however the session cookie was still kept. The question is: Is it possible in Vaadin or Spring Boot to have requests without session have?

If all Vaadin or Spring Boot requests require a session, is it possible to transfer the session without a cookie, e.g. by setting JSESSIONID directly in the HTTP request?
Thanks in advance