Unschooling
I don’t totally buy into the “gaps in the education” caveat.
I don’t know of anyone who doesn’t have gaps in their education.
If your kids are learning the same thing as all the other kids (I, for example, am thinking owl pellets, meal worms and Futhark) you think they are getting a thorough education. Maybe. Maybe not.

(PS - Thanks to the Internet, I now know that Futhark is a real linguistic system. I honestly thought it was some BazFaz that a local teacher made up. It wouldn’t have been the first bit of curricula tried out on the local guinea pigs children. And for all these years, I’ve been referring to it as “FooFark.” As in, “Why are they teaching you FooFark when you aren’t so good at English?”)