unfortunately, in the US at least, rollout of RCS and Chat services will be more or less to the discretion of whatever your carrier has. If your carrier does have some sort of Chat/Advanced Messaging service, it probably only works with other select carriers. Check your own to make sure, though.
which carrier do you have? I have sprint and they have it. Google is working on bringing RCS to all carriers so if that doesn't work you should try Google messages and see if it does through them. I use that anyways instead of Samsung messages and I love it
Read receipts are only for Chat. You get read receipts only if other person has RCS capability. Besides RCS capabilities it depends on your carrier if they support Universal Profile or not. If your carrier supports Universal Profile for RCS chances are you will be able to chat with people on other carrier that has RCS and universal profile.
So far, Sprint are the only ones using Universal Profile.
T-Mobile has been working on to upgrade (for now only tmobile to tmobile and on supported device only).
Verizon is also working on to support Universal Profile through Jibe platform(Google's RCS servers). For the time being only Pixel devices support Universal Profile on Verizon, other devices that do support RCS on Verizon are through Proprietary system.
ATT uses their own Profile for RCS and doesnt support cross carrier feature.
Hope this helps understanding where RCS stands in USA. It is not OEM's fault at all. It is Carrier's in US
