The X-men battle each other, but leave a minimal impact.
A balanced conflict goes a long ways towards crafting a compelling narrative. While it's possible for an arm-wrestling context between the Hulk and Howard the Duck to be entertaining, it's not a struggle that's going to be all that interesting. Civil War II goes to great lengths to create a conflict in which the divisions between characters are genuine, understandable, and intriguing. It's as balanced as any conflict can be and it doesn't even need time travel, magic, or deals with Mephisto.
Creating a balanced conflict in Civil War II: X-men is already a challenge. Before Civil War II even begins, the X-men and the entire mutant race are stuck playing a rigged game while handicapped. They're on the brink of extinction yet again. They're despised, sterilized, and a good chunk of their top characters are either dead, time displaced, or holdovers from an apocalyptic universe. Even by underdog standards, the X-men are depleted in terms of what they can bring to a conflict.
This makes the tone of Civil War II: X-men so distinct compared to other tie-ins. The X-men already lost one war against the Inhumans. Now, they have Ulysses, whose precognition powers may as well be cheat codes. Cullen Bunn goes to great lengths drawing the lines between the X-men, crafting some level of balance between those who want to work with the Inhumans and those who feel they have one too many advantages at this point. Civil War II: X-men #4 maintains that balance for the most part, but doesn't take it far enough.
There's nothing elaborate or subtle about the narrative. This final clash between Magneto's team and Storm's team is effectively streamlined into a single, simple clash. It's light on drama, but solid on details. Andrea Broccardo's art makes this clash visually engaging and well-organized. Mutant battles tend to get chaotic, but since this one doesn't involve time travelers, it's a lot easier to follow.
While the infighting makes up the bulk of the story, it's Magneto who gives the narrative some personal dimensions. More than any other character in this tie-in, he establishes himself as a hardened realist. He now operates on a level that's several steps beyond the debate between his vision and Charles Xavier's dream. He sees the mutant issue as a struggle for survival now and the Inhumans are actively undermining that survival. Giving them an advantage at this point would be tantamount to running up the score.
This emphasis on survival and fighting those who undermine it isn't knew for Magneto. What Civil War II: X-men #4 does is frame it in a new context, one that makes the infighting among the X-men feel somewhat misguided. In this context, Magneto's approach is actually more understandable than Storm's in a backwards sort of way.
Storm wants to work with the Inhumans just like Charles Xavier wanted to work with the human race. However, the conflict with the Inhumans is a bit more specific. A cloud that they unleashed is killing an entire race and they refuse to do anything about it. Working with them has produced little to no tangible results. This makes Storm's efforts to coordinate with them seem misguided. Her heart is in the right place, as it often is, but it disrupts the fragile balance of the conflict that makes the Civil War II narrative work.
This balance is somewhat restored once Magneto gets a chance to interact with Ulysses. This ends up being far more meaningful than any interaction he could have with Storm. The discussion they share is significant in that it forces Magneto to re-evaluate his tactics. However, this meaningful interaction ends up leading to a bland and inconsequential conclusion.
There aren't any meaningful changes that emerge from this clash between Magneto's team and Storm's team. Once Magneto meets Ulysses, the battle just ends. There are no major scars. There are no serious injuries that can't be treated with off-panel magic and bed rest. There aren't even any major consequences to lies, betrayals, and deception. The characters just shrug it off, as though it happens every other week.
What makes this outcome somewhat palatable is the context behind it. Magneto, being a cold and callous pragmatist at heart, sees how this conflict will play out and quite literally. The only way to make sure that he's in a position to protect his people and take on the Inhumans again down the line is to just swallow his pride and leave. It's an inglorious way to end a conflict, but it's perfectly in line with who Magneto is and why he does what he does.
That's not to say there isn't some kind of meaningful impact in Civil War II: X-men #4. It does add more bricks to the foundation on which the X-men and Inhumans will clash down the line. It also supplements some of the ongoing tensions within the teams, such as Magneto and Psylocke. These bits and pieces of progress aren't enough to give the overall story enough weight. It still feels like an overblown round of infighting that doesn't amount to much.
In the ongoing debate between aiding the Inhumans and fighting them, the balance may very well be too fragile to function. Civil War II: X-men #4 only reinforces the inevitability of another clash between these two teams. It also further proves that such a clash may not be a balanced one. At the end of the day, one side still has its movie rights. The other is tied up with another studio. Even with X-men being the ultimate underdogs, it doesn't feel like a fight that'll benefit them in any way.