I'm digging into WP 5.8 RC at this time with a new theme I am building. I wanted to see how this new widget screen worked. What is funny is that I suddenly realized there are no title/heading fields to the block widgets. I'm like, no, really? seriously? If I use the new Classic Widgets plugin to revert back, the title fields are still not there.

I also discovered a nice feature I put into my themes which allows the user to change the blog post excerpt word count, rather than do a global function that cannot be changed. Unfortunately, this overrides the Recent Post block excerpt setting.

I can say that I like the fact the widgets have more options, such as the recent posts and comments, including post thumbnails--now I don't have to code these into the themes. However, I still might have to do this until the Block Widgets are bug-free.

There are a few other quirky things that I am discovering, but I am not sure how to proceed with theme development when it appears the new widget screen method is buggy and missing some important things.