Reximus is going to be around for longer than just a few decades. I will remind that Juvenat is a thing. No, he'll live for centuries unless killed.I'd say our luck has been mixed. We got bad rolls at Gallaborn, Gunnerkrieg and Sverd, but we've got some pretty good rolls elsewhere like Jotunheim, Akar and even during our negotiations with FW Odin in order to get the deal for them to stay neutral.
And I'm not sure I agree with your sentiment since we can deal with him down the line or even just wait for him to die from natural causes. And we can still do stuff to counteract his efforts, he's been having success b/c we've done hardly much for diplomacy as much as it's been his own skills. And trust me, we do NOT want there to be several brushfires when the Titan War ends otherwise we're going to see entire worlds fall. I'd much rather deal with with this guy playing fuck-fuck games for a few decades instead of having the entire sector get plunged into Chaos b/c of a personal grudge.
Also, you say you don't want to take risk b/c of some bad rolls, when the whole thing with making Battlefleet Odin and the Vannaheim Valkyries stand down without a fight is going to entirely come down to luck and we've already had experience with people being too fanatically loyal to stand down against overwhelming odds. And even if we can crush them, there likely will be casualties which we can't really tolerate when shit is just about to hit the fan. The GM has been giving us some pretty big hints that this is going to cause problems if we just barge in swinging our dicks without any prep work. Arguably more than if we just tolerated the bastard.
Next, the brushfire that will occur will be nigh entirely within the Odin Sub-Sector because he has yet to truly sink his claws into the other Sub-Sectors. If he's given more time the aftermath will just be even worse and more widespread.
And trying to play the long game with him is folly. A conflict between us is an inevitability, and the longer it takes for that clash to happen the bigger it will be. If it takes too long it could result in a true Sector wide civil war.
I also feel the aftermath isn't going to be that bad. A lot of little issue of worlds rebelling but really, how many of them would require more than a Companies attention for a turn?
The Odin Sub-Sector has two Hive Worlds, one of which is Vanaheim itself, and one Civilized world. The rest are either agri-worlds or Mining worlds. Vanaheim itself won't be an issue because it will be effectively passified at the same time as we take care of Reximus, the Civilized world would take a turn with just a company or two, and the Agri and mining worlds? Half a company.
The only world that might be an issue in the aftermath is the other Hive World Boer, and even then three or four companies at worst.
And it's not like we'd have to deal with them all at the same time either, it's not like they're going anywhere, though honestly if we had a relatively threat clear turn besides the aftermath of this we probably could handle it all at the same time even if they all rebelled which is doubtful.
It'll be fine. Maybe a bit hectic but it's nothing we can't handle. And as for worrying about what happens when the Titan War ends, they'll still need to recover in their own aftermath, especially the Steel Hatred after getting their asses kicked, before they can really think about attacking us which should give us an extra turn.