Realm very laggy since updating the realm

Our Realm just updated to the latest version.  Since then it’s been extremely laggy—taking forever to render when you teleport to a location or fly around.  It’s so bad that when I teleported to our main location, the (very simple rectangular building) you’re inside was only half-rendered and you could see the world outside because the wall wasn’t visible.  Things eventually render but for some seconds you get to a place and nothing renders or it only partially renders (see screenshots below).  

 

It’s fairly unusable at the moment.