Ok, this was super silly resolution.
I had wrong CE pin selected, and confusion bit me again on the pin vs gpio thing of the header/brcm gpio mapping.
On my rf24 module, I had (from previous implementations) wired up CE to GPIO 22 (pin 15), and IRQ to GPIO 25 (pin 22). So default CE line for rpi/rf24/mysgw is "22" (pin, NOT gpio
The frustration was that my module was being recognized, which gave false appearance of complete wiring correctness, but I think it never transitioned to TX.
Not sure if it would be possible to sanity check RF24 driver to verify if CE line is working in module wiring or not.
Anyhow, moral of the story is to check and double-check the wiring!!!