strawberry guava is highly invasive in Hawaii. they can easily take over native forests there. maybe it's similar to where you are? I've done work removing them manually by hand, root wrench, and an ax depending on the size. when they're clumped in thickets and nothing but for acres, I've seen a push dozer work well, otherwise you can use an excavator. I've also seen a property that never managed their forest and the strawberry guava leaned and fell over and turned into a network of above ground root systems 3-4 ft high that grew thickets on their backs and are in turn beginning to lean and fall over from the lankiness themselves to start cloning more sprouts. was really terrible to see how bad it can take over and choke out a whole forest.
I think the best way to manage it is just to pull the sprouts before they become a noxious weed to the area, harvest the fruit if you're keeping them, add fencing to make sure wild pigs aren't foraging on fallen guava, make sure you have a system to decompose, burn, or chip any pulled trees as they'll self-propagate wherever. I've seen it being used as woodchips for smoking and bbq, so you could also turn it into a business if you have a lot to dispose.
