Have you tried checking your NEMA 2000 connections? There's 3 to look at:
1) the connector from the NRX to the NEMA 2000 extension cable. Check this by removing the screws behind the 2 side plates on the NRX and pulling it away from the fiberglass (gently). You'll see a 6ft or so cable coming from the back of the NRX, and it should be connecting to a NEMA extension cable - check that.
2) that extension cable most likely runs to a NEMA 2000 T somewhere near where your main fusion stereo is - it does in my 2016 C-30CB, at least. Check the T. The T then feeds to your NEMA backbone, and also another line into the back of your Fusion stereo. I'd check all of these connections. If still nothing, Garmin Support is pretty helpful at troubleshooting. If it's dead, the NRX 300 remote is about $185 on amazon, so not the worst of BOAT expenses... only 2/10th of a boat buck. 😉 I just replaced my dead NRX 200 with a 300, and it was about a 10 minute upgrade project.