(Spoilers for confession frontier and digital monster X evolution)

So the basis of the reboot is that the digital world is corrupted and needs to be restored to its original glory. So it deletes everything and sets everything back up to when the world was created. Though it's not identical and geography will be different.

Now that we know what the ever so feared reboot is now let's explain the flaws. The Royal Knights and Yggdrasil are immune to it as they are the admins of the world and need to maintain it. Also there's a virus that makes you immune to it. Wether this is the virus in Tri idk. It is called the X-Antibody Virus. It grants digimon a new evolution that is very powerful and also makes the digimon very powerful. Alphamon has it regardless.

In digital Monster X Evolution, the digital world is extremely over populated. And Yggdrasil has become corrupted and evil. But regardless he makes a virus that makes digimon stronger and immune to reboot. Then the Royal Knights set off the reboot. Now all that's left is the infected and a few that somehow made it through glitches in the system. But over all the infected are blamed for this reboot. Either way the Royal Knights still continue with their mission of genocide. Eventually they realize that Yggdrasil is corrupted and evil, but hey they still commit genocide worse than the nazis.

Now in Frontier the digidestined form into susanomon and use his holy sword to destroy Satan and the digital world.

Well his sword like imperialdramon paladin mode's omega sword, purify data of any corruption or evil. So cherubimon is purified and so is the digital world. And that counts as a reboot technically speaking. So there are some digimon who can cause reboots on their own.

Now in confession we see the reboot happen cause of this new virus and well that's all we know currently. I have lots of theories and speculation but that would be off topic and well too long. I'll do that another day.

Now we know a few digimon can do the reboot and we know the Royal Knights can also start up a reboot. Really we don't know much about the Confession reboot but we will eventually after all six movies are over for tri.

So this is it, thank you very much for reading!!