Any resources on the best physical UI?

I can't speak to best practices, but I can to worst. Tragic Design [0] is a text I've recommend to others in the past. It's important to not just know what to do, but also what not to do and why. I haven't reread it since it came out of beta, I read it a few months before it was published and found it to be good. It gave a lot of examples of poor design decisions with physical systems and analyses of how they led to accidents (or near accidents).

Two examples that have stuck with me:

Descent angle/rate shown and entered on the same display, the mode determined whether you were entering an angle in degrees or a rate of change in altitude. The difference in display, aside from the mode indicator (a single light) was a comma (rate) or decimal (angle). Entering an incorrect value because the pilot thought it was in a different mode resulted in a much faster descent and accident. Imagine this on a simple LED display (but smaller than your standard alarm clock):

  .
  1,000

  
  1.000

And it's not the only control or display in view and those two numbers mean very different things.

Another was a control for a ferry boat with two engines. Depending on which engine, the control for engine speed could mean different things depending on which engine was the active engine. Visual aid:

    |========|
   X          X
   1          2

If engine 1 is active, pushing the speed control away may mean go to the right, if engine 2 is active it means go to the left. The indicator to know which engine was active (as I recall) was the same uniform sized small indicator used for every system status indicator. Forgetting that they had switched engines (to "pull" the ferry to its destination versus "push", due to damage or other issue with the desired engine) the operator accelerated rather than decelerated at the destination.

[0] https://www.oreilly.com/library/view/tragic-design/978149192...

I can recommend you book Design of Everyday Things by Donald Norman.