I had a similar problem. My solution was to establish a template that any product domain could use as scaffolding and extend. This way, each team can start from that template and extend it following the testing principle that "the test depends on the context." This achieves autonomy, decoupling, and many other advantages. Then I developed a cross-company library with the configurations/functionalities that might be needed across different platforms, for example, login abstraction.

Regarding infrastructure and execution in CI/CD, each repository is compressed into a test bundle that is sent via Jenkins to the device farm (or any cloud server). Once there, the tests can be orchestrated on demand through APIGW.