My number 1 pet peeve with MSFS is that it converts my TM Warthog HOTAS (Hands on throttle and stick) to a HOTASAK (Hands on throttle and stick and Keyboard).

The inability to send keystrokes to MSFS from a source other than the keyboard is a real PITA. I know of no other simulations that do this and that includes train simulators, space simulators and all other Flight sims.  My dearest hope is that this is temporary  condition that  MS will make go away in the near future.  I have flown, fettled, built and sat in many (full size) aircraft in my life and believe it or not I have never seen one equipped with a keyboard.  Programming  the HOTAS functions within MSFS is for the birds. I have a TM Warthog  Stick, Throttle and Pedals to use in MSFS and MS put allocated some functions to some of the keys these functions that can be modified but I have found no way to program any of other the buttons/switches on my HOTAS that are not earmarked in the MSFS device control section. I would be quite happy if MS indicated that it would be addressing this issue in the future but that hasn't been mentioned yet.

As an aside I planned a flight in MSFS yesterday from KSBA to KMRY in a C172. I chose the starting point ( a GA parking position the flight planner), I started the flight an just when I was looking a the C172 instrument panel everything changed and the Instrument panel disappeared took me while to figure it out but MSFS parked another (simulation supplied) aircraft on top of my C172.  That's a worry.

Have you looked at FSUIPC?

Yes, FSUIPC will allow putting keyboard presses on any controller. And offers a few commands not available in MSFS itself. More of these 'hidden' commands will come when the 'offsets' are all discovered allowing the Dowsons to add them to their choices.