I am looking for an App that has SMS and possibly RCS maybe
RCS support depends on the device and is also a proprietary walled garden solely controlled by the carriers.
Go use a real messenger that is independent of such ilk: Messengers - DivestOS Mobile
Alternative SMS-capable Apps are available, but RCS is proprietary and not open says the internet to me, so popular Open Source messaging Apps can’t support RCS yet.
Here’s something older from the /e/OS forum … Receive RCS from Android users - #2 by tcecyk - Applications - /e/OS community
The only apps supporting RCS is Google Messages and Samsung Messages.
That’s it. I’d use WhatsApp or something instead.