The best time for the sports drink is during the exercise, then as you said a normal meal after.
You’d want the sports drink during because you’re losing the electrolytes actively while sweating. Having a little bit after the workout helps, but the biggest benefit is replacing the actively lost electrolytes.
Salt on its own won’t replace electrolytes. It’s a more complicated chemical composition than that. (You can find recipes for DIY electrolyte powder than you can add to fluids and they’re usually about a half dozen ingredients or so). I bit of salt in a meal or even a tiny bit diluted into water (you shouldn’t really be able to taste it at all) would be better than no salt at all, but to replace the full spectrum of electrolytes requires more.
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