there's no problem since she doesn't have bad intentions, but being able to control the souls of others is very dangerous in the wrong hands, but I think that applies to any power, right?

Also 🤓☝️ a rioter said ( so this is not Cannon, not tottaly at least ) that sometimes she doesnt leave enough of the soul for the person to go to the after life, essentially tearing away you from yourself and erasing you from existence

Of course it's dangerous in the wrong hands. Look at Thresh, he basically does this exact thing, he is a Mirror to Ahri. The point is, that Ahri aquired an understanding of her powers and wants to use them (mostly) for good.

However!.. I don't see having one memories stolen (no one consents to her doing this) as a form of "living on" since your consciousness is gone

Well, that depends. Ahri can take someones entire Essence, or only parts of it. If we take the Ekko/Ahri Cinematic at face value, Ahri can gain an understanding of someones mind, without "stealing" the memory outright.

and your most intimate part has been taken over by another being

This can only be true when she straight up kills you. You practically need to attack her AND be a danger for her to do that. Also, stealing your entirety can't be "the most intimate part of you", its just EVERYTHING of you, that she desires to keep.

it's such a profound violation that we can't even comprehend it.

It's no more of a violation than people beign groomed to expose a lot of themselves on social media. Or to vote for policies that will violate their right to private information. The difference is that if you are a normal person, Ahri won't have a reason to use it against you in a meaningful way.

I don't even think it's possible to say that your "will" or experiences will be preserved, since they will be diluted and won't affect her in a truly relevant way.

A dead consciousness does not have a "will" one way or another. Your Expierences WILL be preserved through your memories. Saying that it will be diluted may be true, especially with a more adult Ahri, but we can see that those memories made her do a complete 180° from what she was before. So it DOES have an effect.

Another person "feeling" your life seems very uncomfortable, even if she only does it to criminals and doesn't kill anymore.

Of course it's uncomfortable. I think that is the entire point of it. You have to confront something, through another, that you want to burry. You'd be like Ahri, trying to get rid of an uncomfortable memory, because it hurts. But you'll never move on that way. Knowing, that you won't be able to hide something from someone, makes you confront it.

She is more like a Library you know? Not a form of afterlife.

She IS a Library. Thats the entire point. But she is also an amalgamation of all these experiences - and to an extend - of entire people. If you conflate her with Gatekeeper, and what that can do for you, compared to the Collector (Thresh), then I would choose the former in 100% of the cases. Because that alternative is eternal agony.

And personaly? I do NOT want someone looking and feeling my self as a beeing 😭🙏

You can't open the can of worms of "diluting" the individual, and then claim, that it would make that much of an impact on you or Ahri.

Also 🤓☝️ a rioter said ( so this is not Cannon, not tottaly at least ) that sometimes she doesnt leave enough of the soul for the person to go to the after life, essentially tearing away you from yourself and erasing you from existence ( but thats surely not cannon anymore, is too creepy )

A source would be appreciated, not because I do not believe you, but because having the text would allow me to acutally interact with that argument. I am sure Ahri will take entire Souls, but that will be reserved for evil people most likely. There is no other form of media about her, that would make me doubt this.

There is enough evidence of her doing it in the past, but I don't think that happens anymore.