This might introduce breaking changes to the plugins and themes you normally use. For example, I couldn't add a new field - programatically or using a plugin.
The fix
Remove the blocks and revert to using the shortcode:
I haven’t touched WordPress in years but was just looking back into it and was surprised to see this new (to me anyway) Blocks model. I certainly wouldn’t be surprised to see them breaking older themes and techniques. I haven’t dived into it enough yet to see what purpose it serves or problems it aims to solve. I’m coming in a little skeptical about it, though. If it’s one of those things to try to make it easier for the technically challenged but ends up making more advanced techniques difficult or impossible I’m not a fan.
A decade ago I tried out at Automattic in a support role and remember how much Mullenweg seemed to be focusing on winning users who wound up going with Wix or Weebly or whatever the super simple competitors at the time were. I wasn’t convinced that trying to take a more advanced product like WordPress and dumbing it down for non-technical use cases was the best idea then and I still don’t. It might be better to just create a separate product for that, even if it’s based on WordPress underneath.
If it’s one of those things to try to make it easier for the technically challenged but ends up making more advanced techniques difficult or impossible I’m not a fan.
In my opinion, the issue in this post is an outlier (although a surprisingly bad one).
My experience with blocks (or the "Gutenberg editor") has only been in creating custom blocks, I can't speak for using built-in blocks or blocks bundled in plugins.
With this context in mind, I've really liked this new editor used in conjunction with the "Advanced Custom Fields" plugin.
And you can still use those old page builders like Visual Composer/WP Bakery (which I hate) or create templates yourself for each page, this is just another tool.
I haven’t dived into it enough yet to see what purpose it serves or problems it aims to solve.
I know of a project which is a good example. Very large website, but most of their content is written by non-technical people (regarding the web).
They have a small team which makes custom blocks and dictates how they are used by other people when posting new content.
I think using blocks helped them to maintain and improve a cohesive design even with so many people editing the website and after considerable years.
I wasn’t convinced that trying to take a more advanced product like WordPress and dumbing it down for non-technical use cases was the best idea
In that regard I reckon this is a step in the right direction for the WordPress ecosystem (but again, my experience is limited).