Usually, when move the field groups around when editing a post WP (not ACF) will remember the order and it’s working for me when I do so. WP remembers this by setting a usermata value with the order of the meta boxes the last time you save a post. If it’s not working for you then there is something on your site that is causing it outside of ACF.
Are you using GuberbugGutenberg? That might be a cause of the issue.
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