Hi David
This is Nigel, Toolset Support Leader.
I wanted to jump in here to give you a straight answer based upon the current position, which may evolve.
As I'm sure you are aware, most of our developer resources this year have been focused on supporting and enhancing the Block editing experience (Gutenberg) to make it a viable alternative to page builders. We are nearly ready to release the first production release, but that is just the beginning, and improving upon this will continue to be the main focus.
We know that some users are not enthusiastic about that, but the alternative is jumping every time Divi, Beaver, Avada, Visual Composer, Oxygen, and the current favourite, Elementor, snap their fingers, just to stand still. Meanwhile, they enhance their products and encroach on our functionality. I'm sure you can appreciate that's not sustainable.
We haven't done a great job of keeping on top of minor compatibility issues that have arisen with page builders this year, but the changes to Divi are substantial. When the new developer experience was released, one of our developers spent two days investigating and concluded that it would require a substantial effort on our part to work with the new builder. It is effectively a new product under the same name.
I won't rule out that we will add support for it in the future, but it is not in our current plans.
Right now, prompted by the issues which arose with Divi 4 even when using the classic editor (which is the only editor we support), there has been a flurry of activity to clear the backlog of issues which have accumulated, which is taking place in conjunction with Elegant Themes.
So, soon, we should be in a position to say that the Divi integration works as expected, understanding that this means with the classic editor.
It may be possible to support the new builder in the backend, we would like to be able to deliver that, but it very much depends on available resources.
You are welcome to submit a request for that (at https://toolset.com/home/contact-us/suggest-a-new-feature-for-toolset/), being clear what it is you are requesting, namely support for the new builder experience in the backend.