The mountable gadget I'd like to see

[GoldOxide_imp]

In 2021 I believe our smartphones are always with us, they make any extra gadget almost redundant. But yes, I know batteris can run dry, designated GPS devices don't depend on network connection so they can prove useful in remote areas, and when riding abroad I'd usually rent a navigation system with the bike.
At home I don't have any gadgets mounted on my bike, I know all the roads in the country and I know the weather is always hot, so I don't really need any of those things, and the phone is always in the pocket if needed. When we ride in the mountains and get lost we just look for higher ground and that would help with determining an azimuth, that's usually enough.

'14 CB1100 STD 5 speed

Yes. And heck, your smart device (e.g. phone) likely has a digital compass application anyway - and a pretty good one too. No GPS or network required.