Garfly,
I have the SkyEcho 2 teamed to RWY (OzRunways) on a Samsung Tablet.
I have only set it up as ADSB-In till I sort out the Trig TT21 ADSB Out status.
I can see both the light blue (ozRunways) swarm and the dark blue (ADSB) swarm but no ADSB Out from the (my) planes TT21 in flight, because, I suppose, it hasn't activated the ADSB Out because there is no GPS source.
ADSB Out is a project in progress but ADSB In works well, I have, during the Covid Lockdown, been tracking heavies as they fly over the house at 1500 ft.
On long flights, out of mobile range, ADSB is the only way to get situational awareness. Telstra is getting better with a range of small 4G Cells being installed at remote sites but they are not contiguous and the OzRunways swarm can't be seen (and planes on lesser mobile networks can't even transmit their position).
Cheers