Not correct .
RTP is from theclearinghouse and Zelle is from clearexchange.
Zelle came from a mix of banks trying to address only P2P scenarios.
RTP goes beyond to B2C and all other combinations .
Zelle is owned by Early Warning Systems, a wholely owned subsidiary of the top 7 banks in the US. The Clearing House is a joint venture by the top 25 banks in the US.
Clearexchange was purchased by EWS a few years ago.
The times I’ve used Zelle to send money, it has been real-time.
Once I've sent money to someone a few times it's typically instant, but it isn't always.