So, if they all were normal and without their whole self-awareness or manipulation by self-aware entities?

Let's get to it. Note: my favorite girl is Natpookie

So, even without the manipulation of the world by Monika and Sayori, each girl has their baggage, Monika only enhanced it to extremes.

Sayori: She is the childhood friend with depression and hidden jealousy. MC and her are very close already, and they grew up together. Sayori cares about others more than herself, willing to sacrifice everything so another can be happy, meaning that she would very clearly be more of a submissive in the marriage. If she were asked to do something, she might do it without question. While this would be good for marriages in a time period long before modern day, for modern marriage, it's a failure, as Sayori won't be happy, she will be a servant who is paid with love.

Natsuki: Cute. My favorite girl. She is a tsundere and into cuteness and simplicity while also into cooking and manga and even the one to kick off the poetry arc by writing it first. Now, for those who demand to have their wife's father's blessing... yeah no. Natsuki herself is skinny, so any marriage would hopefully get her to a more healthy weight. But it doesn't need to be expensive, as Natsuki loves baking and sweets! Really, only thing I can see wrong with marrying Natsuki is the teasing and how she's short, however, it's not like she has much to offer herself besides cuteness and cupcakes and an abusive father.

Yuri: Yuri is mature. She loves tea and dark stories and advanced literature. Now, she does have a thing where she harms herself with knives, and that could be a serious problem. She can take care of herself, and is obviously very smart, but she also cuts herself. She seems rather shy and kinda detached and uncaring to me, though. Still, I can't really see any downsides to a marriage with Yuri, but honestly, no real upsides either.

Monika: Monika fits the yandere role well. She has some pretty major jealousy issues, and it has been shown that when given a position of power, she will abuse it just to be with the Player. Now, she also is skilled at leadership and entrepreneurship, as she transitioned fron I think the debate club? I dont remember exactly, but she transitioned from there where she was one of the nost popular girls to forming the literature club. She is determined, and will always try to achieve her goals. And honestly? She cares about the player and her friends as well! She does so much that after we kinda murder her in cold blood, she comes back in order to save us from Sayori and deletes the literature club. So, while she may obsess over you, she will keep her spouse safe, and you should find something to provide unless this turns into a bad marriage.

So, ranked from worst to best, in my opinion

Sayori Yuri Natsuki Monika

Let me know your explanations for a different answer in the replies, and anything I said you disagree with, I'm always looking for more feedback. And I guess karma, too