Just my 2 pence.
Really should re-think store-bought, or at least be careful to read labels. Most (not all) commercial rubs are mostly salt. If the first ingredient listed is salt, put it back. That’s a problem because if you brine (and you definitely should!) and then use commercial, you’re double-dosing on the salt.
I always wet-brine all poultry in 6%. Since all salt is different, I go by volume, not weight. Here’s a simple recipe: put one cup hot water in a two-cup measuring cup. Add kosher or sea salt (no iodized please, that’s only for de-icing the stairs) until level gets to 1 1/2 cup level. Stir and dump slurry into 1gallon cold water. Done.
Almost everything else, I dry-brine in fridge. Salt-pepper-granulated garlic. I usually brine overnight, but you’ll get benefit even after an hour or two.
I’ll apply the rub about an hour or two on the counter before the cook. Not much flavor sinks in; I’m going for killer bark.
For poultry, we like Simon&Garfunkel Rub (you know the ditty: parsley, sage, rosemary & tyme).
For beef try: 4 Tbsp fresh ground black pepper; 1 1/2 Tbsp each Tyme, Rosemary; 1 Tbsp each onion powder, garlic powder, paprika, cayenne and maybe a little sugar and dry mustard. Makes about 1/2 cup. Then experiment! Once you find what you like, you’ll be putting it on everything. Besides, if you mix in bulk it takes less time than cleaning your clubs and you’re good for months. And tastes waaay better.
Brisket? I’m from Texas; we use Dalmatian Rub (salt & pepper) and don’t even think about asking for sauce….