I wanted to see the update on the world I've been continuously using for a few years.  The game itself was almost unplayable... blocks don't break, I couldn't place anything, chests wouldn't open, and I drowned while appearing as swimming on ground.  I had to wait up to 20-25 seconds for any actions to occur (like going to sleep). My world is large (620 MBs) and was already relatively slow when in the relevant area of my current village, but I'm hoping there's a patch to help the 1.18 world blend.