A mixed fleet is probably optimal. The Grippens are far more pragmatic to form the bulk of our fighter capability. A stealth fighter has unique benefits so keeping the 16 already committed to isn't unreasonable until 6th gen and beyond can be procured from actual allies.
The big mistake here is going all in on 88 F-35, when the future of aerospace defense is AI drone and missile/counter-missile defense. Not just because of American backstabbing. It's costs far exceeds its strategic value and in true Canadian fashion our defense paradigms are always one to three steps behind.
Edit: Militaries win with effective + cheap + scale. Not ultra-expensive showpieces (heh) with critical flaws that do not scale.