Is there a term for a sort of cooperative homeschooling, where a child provides input and a parent sets limits? For example:

the child chooses the theme or goal
the parent provides a menu of activities on that theme that cover what the parent thinks is appropriate to learn, that hopefully will be enjoyable; as the child matures, the parent explains their reasoning without giving up authority
the child chooses items off the menu, working on them in the order and for the length of time they would like
the parent chooses the next menu based on what has and has not been covered adequately
the child has the option to change the theme when they're ready (within reason - not mid-day!)
the parent has the option to direct the child to the menu if work isn't getting done naturally

I do see the issue with credentialing at middle school level and above, but for elementary, this seems like it would work. Says the parent who is terrified of the whole concept.