Can't open inventory, open chests, objects and mobs have frozen. Save and exit hangs on the save

I can move around my world ok, and I can ascend bubble columns.  Redstone machines have stopped, I cannot open inventory or chests and mobs have frozen.  Exit and save hangs on the save so I have to force quit.  Have tried adjusting the simulation distance to all available settings.  Save succeeds at 12 chunks but no others, but the other problem remains