Unmanned makes a huge difference in many ways, surely. There are all kinds of constraints added by the need to carry around a squishy human, and evaluating what can be done without them is not something I’m going to attempt in a comment here but there are a whole lot of possibilities, many of which might not cost in the hundreds of billions of dollars.
We've been keeping squishy human humans alive in planes for a while, we already know how it works. An autonomous aircraft would require you to develop a high sophisticated computer/AI model that can do basic pilot tasks which will be a big part of your development cost. For now, sticking a human in his much cheaper. Sure, you might save money per unit and in the long run, but the development cost will most certainly be much higher.
You also need a reliable way to communicate with them, so you'd want a constellation of military communication satellites. Not sure Canada currently has that, so factor in the cost for satellite development a bunch of rocket launches.
Even if the attempt failed it would be a better use of the money.
If the attempts failed, Canada would be left without a fighter jet. If that is an acceptable outcome to you, you might consider not spending money on it at all.
But if you want to have an operational fighter jet in the short term, buying one is the only option.



You'd need to get very creative with the definition for it to include a random hand gesture ...