The Global Developer Service Alliance (GDSA) is a kind of one-stop pipeline for developers, by which their apps can be uploaded to the in-house software ecosystems of 3 different OEMs simultaneously. However, these companies have asserted that they are not gunning for Google's Play Store with this new initiative.
https://www.notebookcheck.net/Xiaomi-Oppo-and-Vivo-reportedly-team-up-to-form-their-own-app-distribution-platform.453234.0.html