its not about riding a size too small thats the wrong message to take away from what I was saying, its riding the correct size frame that fits you to start with.
the road bike I have currently is definitely a frame size too large for me, even though I pass that rule of thumb test about the front hub view with the handlebars ,because my hands naturally only come to rest only on the crossbar part of the handlebars in a resting seated position, not the hoods or the drops, I have to reach or lean forward to do that,or rotate my pelvis forward which introduces certain saddle front area interactions which lets not get into.
so I can fumble around with all the various things that can influence comfort in that position, and Ive developed a setup that works for the majority of rides I do, though I noticed with age flexibility does decline which can make it harder on longer rides, but fundamentally the frame is a size too large and Id guarantee thats what a bike fit would comeback with for me.
my next road bike will be the frame size down, at which point Id have to rework all my "comfort" settings on the bike, probably ideal time for a bike fit then, to find the same equilibrium of setup to comfort, but being on the right sized frame should push me 80-90% of the way there.
I didn't suggest it's about having too small a frame size. My point is to show the impact the wrong size frame can and does have.
Your message was clear - "
moving your saddle around and it doesnt fix it, then maybe you do need a bit of proper analysis and a second opinion to sort it out, and
almost certainly the problem will be actually youre on the wrong size frame and your body just cant adapt to fit it comfortably." This is the wrong conclusion after doing nothing more than "moving the saddle around." I pointed you to other considerations that influence bike fit, which you seem to ignore.
Your post above demonstrates precisely why a professional bike fit before purchase is so important. The rule of thumb for the front hub is new to me, I've never heard it until this thread. It may have been true decades ago when bikes were all similar, today the huge variation in frames probably renders this and other established rules of thumb outdated. Your comments about reach should have warned you the bike was too big the first time you rode it. Buying from a physical store with, ideally, a bike fit would have prevented this.
I've used the same LBS for 25+ years for everything. They have set up my bikes using rules of thumb, tape measures etc. Always OK and comfortable. The owner knows me well. In March this year I had a bike fit. In May I ordered a new road bike, and gave my LBS the measurements for set up, the owner asked me if I was sure? He stated "it's not what I would give you." We went ahead with the fit measurements. The outcome was a significantly improved position which lead me to have a fit for my other bikes, making some very real changes. These changes significantly improved my position and comfort on all three bikes.
I'm not criticising my LBS, far from it, their knowledge has hugely improved my cycling enjoyment over three decades. However on bike fitting it's clear to me decades of "rule of thumb" and tape measures no longer compare with the outcome of a professional fit. The improvements are significant, increasingly so as one ages.
Professional help of this type isn't limited to cycling. I could point to other examples that give similar improvements when professional advice is taken. Self-medication is rarely the answer.