[Coldsaturn]

No I completely agree with you! I feel the same kind of frustration with the writing. Especially because at times it's so good, and then it fails spectacularly on things that should be basic.
In a way it's a testament to how much potential the story has, because we wouldn't give a damn if the plot didn't make sense at all. It's when it doesn't meet the standard it already proved in the past that it makes people pop a vein or two.
Then there's also the matter of the different writing teams for the different LIs, and some of them deliver more than others with regular consistency.
Let's say that Caleb's branch will make sense on the whole, and will also be compelling in terms of conflicts and plot twists. They had problems setting it up, but once the ball is going we'll be mostly fine.

About MC and her occasionally very stupid decisions... it really helps me that I don't self insert, some fans go through the 5 stages of grief t every update and card because of the things she does and says.
I find my peace thinking that she really is like a totally different person with each LI (it will get to the point where in text messages she will say to one LI "please, I'd never do X" and then X is exactly what she'll happily do with another LI lol), and based on the situation she is smarter or more mature or more grounded with some partners than others.
With Caleb she is the little sister who's always been overprotected by her big bro and now she's finally standing on her own but is still on the threshold of proper adulthood. This too is easier to see in the Chinese version, the dialogues are leaning toward that dynamic so much that I would never guess that's the same woman who negotiated with sylus and almost killed him several times.

Some fans change hairstyle (sometimes even face) between one LI and the next and tbh I'm almost tempted to do the same, just to further help myself distinguish between all her different personalities.

BTW those legitimate reasons Caleb couldn't contact us haven't been revealed yet, so you didn't miss anything from the main story till now! Those are some very good theories though. I'd be thinking the same in your place.