Isekai heroes are a mixed bag. They are blatant fantasy fulfillment, but it's the execution that matters most in that case. This manga adaptation is unfortunately mediocre in every sense, which I don't know if it's a flaw of the source material or of the mangaka adapting it. Perhaps because of that middling quality, it's something of a guide as to the errors that one should avoid in such isekai stories. Ex Lost, son of the knight commander of the Landry kingdom, suddenly recollects his past life and realizes he is now living in the world of an otome game. He awakened at the moment whenthe "villainness" (and Ex's childhood friend) Alice is publicly dumped by the prince, her betrothed. Ex instantly notices changes from the original scenario and realizes that the heroine Maria is also a reincarnator like himself, so he quickly acts to protect Alice (his favorite character from the game) and neutralize the situation by jumping to propose to Alice in front of the entire court. Luckily for him, Alice has had a crush on Ex since they were children, so the face-saving gesture aligns with what she wanted in the first place.

In many ways, this manga is in an unseemly rush, sort of like the mangaka is saying that we all know how the isekai story will go. That's unfortunate, since I think a lot of characters would have benefited from being fleshed out more. Fitting for a romantic isekai, there's a lot of focus on the love Ex feels for Alice, but the problem is that it's not balanced well. Ex gushes over Alice twice or thrice a chapter, while the story challenges are given less attention. I get it, Alice is cute, the mangaka captures her adorableness quite well, but Ex is too busy insisting on quality time with Alice and complaining about the work that takes him away from Alice. That rather hurts the story, especially since Ex is not challenged often (if at all) in the conflicts of the tale. He lacks the charisma of someone like Arnold Hein from 7th Time Loop, so his victories are neither catharsis nor fun. This ultimately brings down the overall quality of the story since obsessing over the heroine the way Ex does is not as engaging for me as the plot elements which are glossed over.

It's clear from the plot elements that this story got the ax, but it was inevitable, I suppose. I can't say it stands out from other romance isekai manga, so I can't say you haven't seen this before. If you like romance isekai, then you should read it, otherwise, just leave it for a lazy afternoon.