All of the following does sort of assume that there's not a major bug introduced by the update. There seems to be a big problem.
The issue has reportedly been fixed.
It's everyone's favorite holiday that means more work instead of less work, ArcGIS Online Update Day!!!!!!!!!!! I've been looking over the What's New page and trying a few things out to see what you can do in Experience Builder today that you couldn't do yesterday and it's a lot. This is a big update. I don't see any huge new features, at least for my applications, but many of the small updates to existing widgets are absolute gamechangers. I'm going to go over what I think are the most important new options and some first thoughts of what you might be able to do with them.