We all start off mostly ignorant about how ignorant we are, and mostly ignorant about everything else as well.
We can grow more knowledgeable about the world. Some skeptics or relativists doubt this, but it’s obviously true for anyone who isn’t merely defending a thesis.
We also grow more knowledgeable about our ignorance. It’s something we’ve all experienced. It’s difficult to do, and most of us never get very far with it.
There are different kinds of ignorance. Some things we could learn but can’t afford the time for. I’d love to get a PhD in economics or physics, but I doubt I will ever find the time. Still, it is greatly valuable to be aware of the areas of knowledge which are known which I myself do not yet know.
There are other questions about which all people are currently ignorant, though someday we might have knowledge. This is another sort of ignorance about which it’s invaluable to be knowledgeable.
There are questions which might have a good answer somewhere in, say, the world of philosophy, if I could search long enough through all the different things that have been written.
There are things I’ve learned but forgotten or gotten confused. There are things I might have learned incorrectly. There are things no one will ever know for sure. There are things that don’t need to be known because they’re simply unimportant.
There are a thousand flavours of ignorance. The true philosopher, it seems to me, will be a connoisseur of the unknown.