The left / right is a non issue for me. There are other far more pressing ergonomic issues in the cockpit than that.
And as for
how engineers design that interface.
When I had dinner recently with the guy that designed the pad that you rest your hand on in the A380 when entering data into the MCDU, I was most disappointed to discover that it did not come to him in a Eureka moment in the shower or the middle of the opera. Boringly it came slowly over time, being built on other ideas.
