For what it's worth, on sportbikes, best fork oil level with the proper springs
will typically fall in around 5" to 5 1/4" down in the tube, springs out, fully compressed. That's because the variables on forks aren't so great in sportbike weights and the service conditions. These have very soft springs in them so use a higher than typical fork oil level to add spring progressivity, trying to compensate for the heavier riders that will wind up on them without being too dangerous, with limited success.
The factory spec on these is 4 5/8" down, pretty high on average, higher than it would be with the optimum springs, but due to the factory not knowing the weight of the rider purchasing one and their very soft
stock springs. The suspension on these is full of compromises due to not knowing the rider variables and.... I still don't really know why they spring them so absurdly softly, but.... I'd hate to think it's to make their other bikes feel so much better and justify an "upgrade" to another bike ar a later date but I really can't think of any other real reason. And if it's true, that's not very nice.
Not nice at all.
But it can be fixed as outlined in other threads.
And one more anecdote from my own experience. I have older CBR-1000F's as my street bikes, touring bikes. They are heavy (608#)
and as such, never even had the ready option of changing springs because nobody even offered one stiff enough. And the stock ones weren't THAT bad for all but hard riding. They also came with Honda's first cartridge shocks, nice for the time. What was particularly annoying with the stock front was the propensity for bottoming out under hard braking and hard riding, especially at the track. Yes, I track rode it sometimes.
When deliberating what to do with it, excessive static sag and propensity to bottom under hard braking, and then seeing that the stock fork oil level spec was something like 6 7/8" down in the tube, I decide to go with a new spring spacer to get the static sag up from 2 1/2" to 1 3/8" and raise that fork oil level to add progressivity and then settle for whatever improvement I got. Ran it as high as 4 3/8", a full 2 1/2" higher than spec, and did fine with it. It would still bottom under the most extreme braking but was still way better all around, helped the bottoming except in the most extreme braking. And the point in adding this story, the oil level was first changed on that bike when it had about 25,000 miles on it and the fork seals never leaked until after 90,000 miles, at least half of which was put on working it pretty good on extreme mountain twisty roads. And when they did finally fail, it was the typical environmental damage and age that did them in, not just the wear from repeated sealing of pressure. I don't know that I would go more than that on any bike
and for the reason that the real design and service parameters are really similar, one bike to another (that's why I did what I did but didn't try more), but they aren't glass, either. I hope that adds something specific to the conversation but doesn't it really encourage reading up all the more? Gain some undertanding of these parts even if no change to hardware will be made?
Good luck, all!