> please tell me ONE app for Android other than Google Messages I can use to send and receive RCS, it surely won't be problem since it's international standard same as SMS, so there must be plenty apps available...

Nice red herring. The number of implementations is irrelevant here, although Wikipedia says Samsung had one too.

Here's the standard, try Ctrl+F "Google": https://www.gsma.com/solutions-and-impact/technologies/netwo...