My son is having the same problem on his Xbox One S Xbox One X. When Launching Minecraft, the game takes over 5 minutes just to load to the main menu, and another 5-ish just to load a world.
I do not have this issue on my phone, my PC, or his iPad.
This is on the most recent version, 1.20
This just happened to me and hour or so ago. I was going to fight two Withers, one after another. The first Wither behaved appropriately I guess, nothing weird. Second Wither dashed straight down at half health, carving a perfectly square hole about 60+ blocks (was at about y75, Wither dashed down to y15).
It went straight down into a huge cavern, and it was a pain to finish the fight, with all the blocks laying around from the first Wither, and then from this one going straight down, the game became very laggy.
Bug is still present, but I'm now very skeptical it's a Minecraft issue.
I can't speak for everyone, but this seems to be an android issue. I have been playing Lego Fortnite with my son and it's behaving the exact same way, which is just as annoying. In menus, it will scroll pages twice at times, and it's infuriating when trying to get to a specific page.
That's probably my last edit, until the true culprit is resolved. I'm sorry for all the irritation the devs received from this issue. I apologize. Once the issue is fixed (by devs outside of MC) I may edit this post again just to say so, but at that point I didn't feel like it's necessary.
I have edited my post with this information.