Certain things are universal with respect to the human form, regardless of proportion.
There is a ton of info on all this. it is worth figuring out what works for each individual, IMO. None of it is complicated, and all of it is dictated by each person's body. obviously fitting the bike to the body is important, and more so as you put more of your body into the ride.
The reason people say to set the saddle first is because the greatest load by far is through your legs, and if you compromise your saddle position, you compromise your legs. Forget about losing efficiency---most of us aren't racing. The issues are knee and to a lesser degree hi strain, and odd strains on the rest of your body--e.g. too much weight on your hands (wrist/elbow strain) and reaching too far forward and down (neck/shoulder strain) all of which doesn't always show up in the first 20 miles but which can really hurt over time---or even cause injury.
On my old Cannondale, I have the seat a little far forward, less than half an inch, further than on all the rest of my bikes .... or I did until I found that even after 15 miles I'd get a slight but painful twinge in my right knee. With the saddle forward I was coming down to o straight on the knee, i guess, and since my right leg is stronger, it was showing signs of injury first.
You young guys can adapt a lot more---but that doesn't make it better.
Absolutely there is an optimal orientation for Each Rider---depending on upper and lower leg length, foot length, cleat position of foot-on-pedal position, lean angle .... where the seat offers optimal support, the legs get extended enough to really engage all the muscles without hyperextending, and where the rider will, over time, find the greatest comfort.
Saddle height is really important, but so is fore-aft positioning--more so depending on whether you are really fit and riding time trials, riding distance, just a normal person riding around the neighborhood at seven mph, or an amateur enthusiast or whatever ..... If you are a a 7-mph stroller, you can have the saddle way too low and not feel it because you never generate enough force to cause strain. If you like to attack hills and occasionally push, knee extension determines whether you will eventually need knee replacement.
Unquestionably, if you ever ride with a lot of effort, since you are basically putting all the force you can generate through your legs into the pedals, get the saddle set up right so the legs are working properly.
As for this person (the OP) it could be that he has the saddle angled up and is leaning down. he might need spacers, and/or a shorter stem. But his saddle is all the way forward --- possibly the frame is too long and he will Never be comfortable.
Based on the info we have None of us know what he needs.
[MENTION=526099]Rolla[/MENTION] really hits it---visit
https://www.bikeforums.net/fitting-your-bike/ and figure out for yourself where you need to be on the bike, OP. Everyone has different proportions, different amounts of flexibility, different comfort zones, different riding styles .....
Maybe also chaeck out
https://ilovebicycling.com/fore-aft-saddle-position/
I use KOPS (knee over spindle) as a loose guideline , a starting place to make further adjustments. I generally prop up my bike against the washer-dryer and put a tool box or something on the other side, so I can sit upright with one foot on the pedals and the other providing security, and make minor adjustments. However, I have been riding so long I can usually feel what will work for me. The OP might have to develop that sense through trial and error.
I do Not recommend paying $300 for a "Pro" fitting unless you are already pretty well dialed in and are seeking that last few percent of efficiency. The basic stuff can be learned online, and can be figured out through trial and error. It's not like nobody could properly size a bike until lasers and video were developed.
Particularly for people who might need to be buying a new bike in the right size, dropping a few hundred to be told what you could learn in a couple hours of reading the Internet and fiddling in the driveway ........
And yes, different fitters might have completely different set-ups----if they are hacks.
Hack fitters might try to force everyone into a particular fit---long and low racing posture, for instance---while a good fitter will ask the rider how s/he rides and set him/her up in a more realistic manner. But in any case, simple physics and physiology determine where the saddle goes relative to the BB. On all my bikes, even my mountain bike, the saddle/BB relationship is almost identical, because my body doesn't change from bike to bike. If two fitters cannot find a very similar correct seat position for a given rider, at least on of them is a fake or a fool.
IMO