RTMP is the default for a reason. Every encoder made in the last fifteen years speaks it, from OBS on a laptop to rack units in a studio, and on a stable connection it will carry a feed all day. Its weakness is the open internet: a lossy path shows up on screen as smearing and stalls, and the protocol has no way to fight back.
SRT was built for exactly that path. It retransmits lost packets inside a latency window you control, so a feed sent from a venue on shared wifi or a bonded cellular link arrives clean, and the stream is encrypted in transit. If your contribution leaves a network you control, use SRT.
Push and listener modes
Every SRT link has a caller and a listener, and gear can be opinionated about which role it plays. Many platforms only accept one arrangement. A LIVEPLUSTV channel can take either side: push to us the ordinary way, or have the channel listen so your equipment dials in, or have it call out to a source that waits. RIST contribution is supported as well, for feeds coming from broadcast-side gear that prefers it.