Disabling vsync does NOT work for me unfortunately. Neither does F3+A :/
Can confirm this is happening to me too! It's most extreme when migrating older files (doesn't matter how old as long as its pre release 1.14-5 or earlier) but I definitely experience it on brand new 1.14 worlds.
Edit: Also probably useful to know I have a monster of a computer that I use to do hardcore animation work, so it's not my computer! Other heavily intensive games play fine.
I experienced this in one of the first 1.14 snapshots - I thought it was my game being buggy!