@rik It's surprising, but if I use your MMS APN settings with my Google Fi SIM (which gets set to T-mobile values after installing the SIM), then I can send MMS but cannot receive. I do have wifi off and have rebooted.
@dieharddan@kmsgli just noting that SMS in and out now 100% reliable. MMS takes some fiddling with APN to clear out, can't have multiple APNs with the same name (one for internet, one for MMS). But after getting it set, should work in and out for MMS photos when WIFI OFF. WIFI ON is still a problem beyond the P3a.