After updating to 1.13.3, the game loads beyond the splash screen fine, but the title screen/main menu is lagging out severely, like, not even a frame per second. The background panorama is frozen and then will suddenly jump further along. The menu itself takes forever to appear and even when it does, clicking an option results in the game taking even more time to transition to the next menu. It is definitely this version of Minecraft as I’m using in iPhone 8 with IOS 13.1, so I’m as up to date as it gets. Additionally I did not have this issue on the previous version or on my Windows 10 laptop,  where I haven’t yet updated the game.

EDIT: I updated my phone to iOS 13.2 and that apparently fixed it.