Are cheap WiFi smart circuit breakers safe to use in my main panel?

Specialist communities including r/homeassistant and r/electricians repeatedly flag that the inexpensive Tuya-based DIN-rail 'smart breakers' on Amazon are not UL-listed replacements for the breakers in a U.S. service panel. They function as smart relays with adjustable overcurrent and over/undervoltage cutoffs, and are typically installed downstream of a real breaker, often in a subpanel or solar/DC setup. For a true panel-replacement smart breaker in the U.S., a UL-listed product like the Leviton 2nd Gen series is the safer path.