Where is your proof?Hm what.
So you are saying that only Tsunade and Sakura can summon Katsuyu.
Yeah, right.
The seal just allow them to summon more of Katsuyu. Because of the increase in chakra they get.
The seal is in no way related to SM. It's about extremely precise chakra control.
Sakura never ever summoned katsuya until the moment she for the seal. I'm sure Sakura in base based on feats can more than summon katsuya.
Infact she did summon katsuya without using the seal i'm sure you realised the second time she did it with tsunade they opened the seal for some chakra. So confirmed she summoned it on base chakra.
KATSUYA HERSELF said her power is directly related to the byakugou seal power. Meaning she would vanish without it. Therefore it's only logical to draw this link.
I'm pretty sure their SM involved the seal in some way if we were to see it.
only Tsunade and Sakura can summon katsuya unless you can prove me otherwise
I never said it was 100% related to SM but YOU can't say it isn't because you know next to nothing about it other than what we know from the manga, we have just started learning more about it and how it relates to the slugs.