I think the concept of translating existing flexible layout instances into block instances should be possible. Gutenberg blocks are stored in post content as HTML comments that conform to a consistent and predictable format, so editing/updating via PHP is certainly doable.
I think the challenge is how to actually implement the process. A few questions that come to mind: What happens if the user hasn’t yet converted all layouts in the source field to stand-alone auto blocks? Would we drop the new blocks at the beginning or end of any existing post content? Should the conversion be a post-by-post process for the user, or a global edit/update from a single admin screen?
I’m not sure how much time I’ll have to dedicate to a solution but would love to continue the conversation!
Looks like acf_get_field_id was removed at some point. I just pushed an update (1.0.5) that will resolve the issue.
A quick note: You probably don’t want to enable auto blocks in the field group that contains the source flexible content field. Those settings will be added when creating a new field group from the layout.
