As others have mentioned, there is a difference between fatigue from using heavy switches and soreness from the impact of bottoming out.
I prefer to bottom out with every keystroke on any keyboard. Because of this habit, I found it difficult to type on mx clears, because these switches have a rather steep slope of increasing force past actuation until bottoming out.
My favorite switches are 55g Topre and IBM capacitive buckling springs (Model F). I have a Novatouch in my rotation, but I find it too light for my taste. On the other hand, I have a HHKB Pro 2, but I find its 45g switches pleasant to type on.
If your fingers are sore from using your Novatouch, it could be that the switches are actually too light for you, and you are feeling the effects of impact from bottoming out.