As I just read in the document for polylang, this is not possible and there isn’t any way to accomplish this from the ACF site.
Some ideas on making it easier.
Yes, you should use clones, but probably not in the way you are thinking.
Each “Layout” that you use in your Flexible Content field should be in a separate field group. In this main group containing the flex field you “Clone” all of the field groups, one per layout. Then you translate the main group and all of cloned groups. Then edit the main group flex layouts to clone the correct translated field group for that language.
Then when you add a layout or edit a layout the amount of work needed is reduced.
To add a layout create a new field group for the layout, translate it, clone it into a new layout in each of the flex field groups.
If you need to edit a layout you only need to make changes to the affected layout group.
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