As of now, Azure CosmosDb Connector is available for logic apps and Flow services.
So while building PowerApps with Azure Cosmos DB as the backend will have to write Flow/logic apps and then call that Flow in PowerApps.
Wish could avoid writing flows for all transactions that could be done on PowerApps if Azure Cosmos DB Connector is supported for PowerApps as well!
I am struggling with that for a long time and totally agree.
Will you share the methods and flows you are using as alternative connector to cosmos db?