well, you can disagree all you want, but i'm stating a fact. the best fishkeepers in the hobby do partials daily and have seen nothing but beneficial results. It's your tank, you're welcome to do it how you want, I really don't care. Temperatures fluctuate in the wild sometimes in extremes over a few hours, 10 degrees plus at times. I know this from experience and I walk in the water when I go fishing so it's pretty obvious when the water is way colder or warmer the next morning when you were just fishing the same spot the previous day. Rainfall make a HUGE temperature difference at times and PH shouldn't fluctuate much at all considering you are using the same water source unless your water changes are far and few enough in between to allow ammonia/nitrates to cause the PH to drop abnormally low.
IDK why you say that, if you don't have high concentrations of natural bacteria, you shouldn't be doing water changes often because they NEED the nitrate and ammonia to grow and reproduce