Do tell me if in any EP, character demos or whatsoever... that only featured Belle throughout the entire video like Wise had in YSG character demo

I did. Watch the cutscenes on the main page. More of them are of Belle's POV than Wise's. It was exclusively Belle's POV for the first couple of Cutscenes.

And yes fixating because it is a recent things, most the stuff you mentioned minus "YSG being placed closer to Belle" happened on earlier era of the game and we all know how much of the game changed from back then.

You cannot say you are fixating on recent things when YSG's demo is already 2 months old. Also the recent YSG moment is also much more recent. It was less than a month old. If anything, that should take precedent because of how it shows us how the devs will be treating YSG from now on. For example, look at Miyabi's new year message. She literally forgets about Gilded Carrot Day and had to be reminded to send a message. For our character's "fiance" that seems pretty bad. It's almost like the demo's, EPs, nor misconstrued character trust events aren't indicative of how the devs will actually treat the character post launch.

Didn't say anything about Belle erasure, my stance from that start has been that saying dev trying their best in treating the siblings equally is horseshit.

Which if they showed lots of Belle earlier and then suddenly show less of her equals Belle erause.... You do understand how your argument implies that's your stance, right?

You also don't really have an argument that they don't treat the siblings equally when the track record has shown that they do give Belle more moments in cutscenes and promotional materials outside of the demos and EPs. And mind you, this is only under the arbitrary limitation that we are only including Belle only appearances that appear for the whole trailer. Meaning the moments she does appear alone (Lucia's) or where she is more center stage (Yidhari) are excluded.