The way we have tackled this so far is to create an ACF field for “Right Sidebar” and “Left Sidebar”. Inside there we can use shortcodes, but we can’t use blocks there yet.
However, we also did some work to figure out how to use Gutenberg’s “reusable blocks” concept in a shortcode, and make those available to these sidebar ACF fields. In an indirect way, this has made it possible for us to use Gutenberg code in the ACF fields. It’s certainly a roundabout way to do that, and not our primary intent or use case, but it (kinda) works.
I take it back! Some of the updates to WP cleaned up the major admin display glitches we were seeing before. We’re upgrading to 5.0.3 and still using ACF 5.8-beta3 in production.
The caveat – for which we have alerted our users – is that ACF is caching output to memcache, even when there is an admin user updating content. We have to click our “clear cache” button a lot while we are updating content in our ACF fields. That’s not a Gutenberg issue, though – this is an existing ACF problem.
We are using it in production, but we are regretting it somewhat. Waiting for 5.8 to come out means we cannot update WP to 5+ (we are still on the Gutenberg plugin and 4.9.9). For context, we are only using ACF Blocks for things that need to be dynamically generated anyway, so using the familiar field styles and tools adds a level of consistency for our admin users across our CMS.
I am currently exploring walking back the code we’ve written and heading back down the JS/React path, but it’s unfortunate. The ACF Blocks are simple to create and easy to maintain, and we’d prefer it to the fussier JS code in most cases.