S10, S10+, S10e Bluetooth input problems

Just a suggestion, you guys seem much more knowledgeable than me, but I noticed with a recent update, Samsung pushed a Smart Things app to my phone. This seems to be a hub for integrating Samsung products, like TVs, etc. Perhaps this may be what is causing this problem.
 
No idea here either. Which is why I stopped using Samsung - they consider customer service a revenue sink, not a revenue source. Evidently Bluetooth keyboards do work with S10s, so their "it doesn't support input devices" is just a way of getting you off the phone quickly.

If you're in the US, bring an S10 and a keyboard to uBreakiFix and ask them why it doesn't work. Maybe they'll be able to figure it out. (I assume that you've tried the same keyboard with other devices and it works.)