Your new setup is virtually the same as the old one. I had a problem when setting things up a while back and found a WiFi issue. The Raspberry Pi 3 WiFi antenna is at the same end as the SD Card and right on the edge of the board. One possibility is the polarization of the Pi3 antenna is not the same as your WiFi router antennas. Perhaps tilt one of the router antennas or reposition the router a bit and see if your results improve. Any metal items in between the antennas can mess with the signals and cause you to lose signals, just a possibility.
Maybe you could have accidentally damaged the ADSB antenna cable. Perhaps check into @adsb5678’s post: Three Easy DIY Antennas for Beginners for some nifty antenna alternatives. Low/No cost, and very capable. I particularly like the V notch one. Have fun making your system better and better.
Gene