I just baked a batch of chocolate chip cookies (https://www.bonappetit.com/recipe/bas-best-chocolate-chip-cookies). I felt like they were just a tad bit on the sweet side, so wanted to know if there would be any negative consequences from reducing the sugar? (like 1/2-3/4 of the sugar in the recipe) Would the cookie not bake as desired or something like that?
Sugar contributes to the texture in cookies. In particular brown sugar is softer than white because of the hygroscopic molasses. If you like your cookies soft I'd reduce/remove the white sugar first (plus you don't lose the brown sugar flavour). If that's too soft you can adjust the ratio in the next batch (or, to some extent, bake a tiny bit longer, but the texture really only becomes apparent on cooking)
Baking time might change a little, so keep an eye on them when they should be nearly done.
Sugar does have an impact on more than flavour, so the texture of the cookies will change. You will have to experiment to find something that you like.
On the other hand - if you don't want to change the texture of the cookies, you could try to replace some of the sugar with Isomalt - it's a sugar substitute that has very similar mechano-chemical properties, but doesn't taste sweet.
It's fine to deduct the amount of sugar, just based on your desired sweetness.
Sugar will do more chemical reaction in Meringue-based desserts, like Macarons or topping creams on cake. It's more likely to impact the result if the sugar amount changes then cookies, which texture comes primarily from flour and butter.
Anyway, just give a try and do some adjustment after tastes :)
(You could make small portion first, then to make normal portion while you've fix the sugar amount based on your desired sweetness.)