Huh. I find ESC easier to type than Caps Lock because it is in the corner of the keyboard.
I used to have RSI and what solved it (over 15 years ago) was taking more care to hit the precise center of the key. Using my sense of touch to sense the key's exact location before even trying to activate the key helps me do that. When the key is on left edge of the keyboard, it is easier to do the determination of the exact location (of the left edge of the key I want) because I don't have to worry about accidentally activating the key to the left of the key I want. Caps Lock of course is also on the left edge of the board, just like ESC is, but ESC is also on the top edge, which is an additional help: the easiest keys to type in my experience are the ESC key and the left control key because they are in corners of the board. (The other two corner keys, "pause/break" and the right arrow key, are harder because of how far they are from the home row.)
I never understood the desire many writers on this site have of moving the hands as little as possible. More precisely, I understand the rationale, but I consider the rationale to be misinformed. If you don't move your hands (i.e., because you have a keyboard with only 36 keys or something), you still have to use your arm muscles to hold your hands over the board, and the human brain is better at movement than at using the muscles to statically counteract gravity like that. That is part of it, but there is more. When hitting a ball with a tennis racket, it is ergonomic to take a back swing, i.e., to move the part of the racket that will hit the ball in the direction opposite the direction you want the ball to go, before starting the swing. Very quick back swings are important in typing, too, for preventing RSI (for reasons I don't fully understand). And I think moving my hands around the board (i.e., in the 2 horizontal dimensions) makes it less likely my brain will put the relevant muscles in "freeze mode", which makes RSI more likely. Or something like that.