Is there a way to find nearby courses on the watch or do I have to use GCM to do so?

If it's anything like the Fenix 5x+, you can show up at the trailhead and -> Start -> Select Run

If the 945 is anything like the Fenix 5x+, you can show up at the trailhead and Press Start -> Run -> Press and hold mode ->  Select Navigation -> Round-Trip Coarse -> Enter distance -> Select Direction.  Then the watch will create 3 coarses with elevation profiles based on heat maps.

Very handy.

The 945 doesn’t have the ‘Round Trip Course’ option in that menu (FW 2.5) - I hope it’s an oversight like the ‘After Sunset’ option for backlight and comes back in a future FW

I have this round trip course option on my 945, FW 2.50. I press start...run...up...round trip course

Yeah it does...

In your activity, go to the menu -> navigation -> Round-trip course