I already addressed this. you're just bringing nothing to the table.
Even addressed one of your other arguments already.
PB isn't being retconned. You people just fail to understand it.
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赤血操術「百斂」
Blood Manipulation Technique: 'Convergence'
血液を加圧し限界まで圧縮する技
A technique that pressurizes blood and compresses it to the limit.
「百斂」で圧縮した血液を一点から解放し撃ち出す
'Convergence,' releases and shoots out the compressed blood from a single point.
呪力で強化された血液の初速音速をも超える
The initial velocity of the blood, enhanced by cursed energy, surpasses even the speed of sound.
赤血操術奥義
Blood Manipulation Ultimate Technique.
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^ from the volume release of Yuji vs Choso fight
It's a technique that ALLOWS you to compress blood to the limit. Nowhere is it stated that the compression of the blood has a general limit for everybody else. How far you can compress depends on you yourself, which the fanbook even points out.
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「百斂」の加圧が大きいほど、その反動で「穿血」の速さと貫通力も上昇する。
The greater the pressurization of 'Convergence,' the faster the speed and penetrating power of 'Piercing Blood' increase due to its recoil
``
And there's more.
"So much pressure!" Which is about convergence here. If there was the same limit for everybody else, then Kamo wouldn't be so startled and surprised at all.
Finally, let's go over the very blatant explanation that you yourself and many others are blatantly ignoring.
First, we have convergence. You compress the blood, that's one step that Choso takes. It now has its own initial velocity. Secondly you take a step further and ENHANCE IT with your cursed energy. This PB created by Choso allows the PB to surpass sound of speed itself.
"The initial velocity of the blood,
enhanced by cursed energy, surpasses even the speed of sound."
This is as blatant as it gets. You can argue all you want about compression having a general limit as a technique for everybody else regardless of the level of their jujutsu. That all does not matter, when enhancing it boosts its speed further. And I'm sure you all know HOW ce reinforcement works.