Substitute actual vodka for storebought vanilla extract
No, vodka is nothing like vanilla extract.

Unfortunately the premise of your question is wrong. The thing that makes "true" vanilla extract true/pure/real is that it's made from real vanilla beans, as opposed to artificial flavors. Artificial vanilla is often just vanillin, one of the key flavor components, and it's been manufactured from another base ingredient (probably lignin), with no vanilla involved.

In both cases, the exact source of the alcohol isn't important, it's just that it's alcohol (ethanol) and water. I've mainly heard of using vodka for homemade vanilla extract, because as far as readily available liquor goes, it's about the closest you can get to pure, flavorless ethanol/water. It's hard to imagine that mass-produced commercial vanilla bothers insisting on vodka in particular.

Anyway, flavors. Artificial and real vanilla extract are really pretty similar, which is kind of the point. If you can't easily get the real stuff, or it's too expensive, there's absolutely nothing wrong with using artificial.

In particular, for baked goods, artificial is totally fine. The heat means you lose a lot of the flavor complexity, and the two end up indistinguishable, or close to it. Notably, America's Test Kitchen has done vanilla taste tests and says "It matters not a whit whether you use real or imitation vanilla, because you can’t tell the difference when you bake."

The difference is much more noticeable in things like icing/frosting, pudding, and ice cream, where you don't use much if any heat after adding the vanilla, so the complex flavors remain. So if you're making any of that, and you want it extra good, that's when you may want to splurge for real vanilla extract, or vanilla beans.