User blog comment:Sharaku Jr./Son Goku VS Superman (Death Battle - Start From Scratch)/@comment-36524657-20190917141027/@comment-37960362-20190918152634

The reason why they didn't actually end up destroying the universe is they were nullifying each other's attacks at some points. It has been confirmed multiple times by the Elder Kai and the narrator that they were attacking each other with the power capable of destroying the universe.

Also the description of inaccessible speed ("The ability to move distances, whether finite or infinite, in zero time without the aid of teleportation. This is usually achieved by moving in places outside of time or places where time doesn't flow.") fits in perfectly with Jiren's feat, so I don't really see why you'd only consider it an MFTL+ feat - but I still respect your opinion.