Nothing much, really.
First, a small notice: I don't remember anywhere saying that Control has destroyed things in the future; Control is supposed to evolve as soon as it accesses the sphere data, and then start to destroy things immediately. Dr. Burnham jumps into the future and finds the Galaxy in that state, after Control has done what he's supposed to do. So both her and Terralysium are not that much out of place, after all.
Anyway, aside from this, we have pretty much good evidences that Control couldn't have destroyed much, and that Dr Burnham is a very bad scientist with some serious lack of knowledge about the galaxy and extremely poor math skills. Follow me...
We know for certain, from all the different ST series, that the galaxy is inhabited by a lot of "god-like" figures. Luckily there is no need to stretch it too much and work on opinions , when we have already evidence that some of those beings would intervene for sure. For example there's a guy on Rana IV who can -and has/will have- erase entire civilizations from existence with simply a thought, to protect himself and his loved ones.
So, according to ST canon Control hasn't lasted long: we could already stop here. But anyway...
The second half of the second season of Discovery is just a collection of plot holes, bad ideas and completely messed up stuff, using hyper accelerated dialogues and MichealBay-esque camera movements to distract the viewer and cover for all of it.
- ST is set in our reality, in our galaxy, the Milky Way.
- The current estimated count of planets in the Milky Way is 100 billions, and growing.
- If we count a second (more on this later) for every planet, we get a total count of 3170 years
What does that mean? Well, first, to be able to affirm that Control has eradicated every form of life in the galaxy, Dr Burnham should have checked every single planet. To do that, even if she manages to teleport close enough to a planet and scan all of it for life signs in just a second (rotfl), it would take her 3170 years. Yep, good luck with that.
So the first evidence we have is that we cannot possibly know what Control has achieved.
And keep in mind that I'm hand-waving away other life forms, like those that navigates in the void of space, the ones that cannot be found without specific instruments, and so on. Dr Burnham has obviously no idea of how big the Milky Way is, nor she can do a simple division to realize she hasn't checked anything meaningful of sort.
And, if she can't cover the entire galaxy in a life time...it goes without saying that Control cannot realistically have destroyed it all. No matter how detailed the sphere data was, to be sure to destroy all life in the galaxy it has to physically reach every planet, check if it contains life, and then proceed to destroy it. And unless it has invented a way to teleport and extinguish all life on a planet in less than a second, we're back to square one: 3200 years. Sure, it can build other ships or use existing ones, but it still has to teleport around and fight, even if for a few minutes, and then sterilize the entire planet. It may be possible, sure, after all it's SF, but still...highly unlikely.
Uh, by the way: if our galaxy is like the others, there are probably trillions planets in the Milky Way, not just a hundreds of billions...
(e.g. would really the Q allow for a bunch of circuits to extinguish life in the Milky Way?)