Can online games be produced with the Google Subsystem?

My question is as above. Is it possible to make other online games without steam or epic games?

It is possible to make an online game without steam, epic or google. In the core you just need to transfer information between the client and server. If you want a more specific answer, I would require more information.

By default you can create an online game with Unreal Engine without the requirement of an online subsystem.

How can I do it with Google?