Oh ho! I figured I should avoid this since it requires hardcoding the IP (50.31.246.1), which seemed (at least theoretically) fragile.
But happy to try it!
Oof, unfortunately this seems to have immediately broken all 4 variants, which give an immediate DNS_PROBE_FINISHED_NXDOMAIN error now.
Ah, sounds like that’s being discussed in WebSockets do not work on Custom domain? – thanks!