How do you correct beef BBQ that is too sweet and has no bite?

Sweetness needs a sour or acid counterbalance, such as lemon or vinegar. Be careful though or you could totally ruin a dish by adding too much.

Another alternative is to double the batch, omitting the sugar for the second round.

For a "bite," you could try adding sriracha sauce (my favorite condiment!). This has a tendency to sneak up on you, so add a bit at a time (depending on how much bite you want), and let it blend in, and cook thoroughly before adding more. You might also try cooking (emulsifying) a fat (oil/butter/lard) and cayenne (so the spice isn't grainy once it's added), and then adding it to the sauce.

There are a lot of bottled products such as "Red Bull" and it's hot! (Used to BBQing) Be careful about using it (spread it on with a knife) because not everyone likes red hot anything. This hot product (or another of your choice) will over-power the sweetness.

maybe adding some fresh minced garlic will help. == mix minced garlic and paprika the smoked kind is best but most will work if you just want it to not be sweet. Also there are several good artificial smoke flavorings and they'll help cut the sweetness. If it is really thick and sweet sometimes adding a bit of strong black coffee can hep cut the sweet. Even if you want it hotter, try to neutralize the excess sweetness first since it risks turning into a sweet AND hot mess.

Adding a bit of cider vinegar will help cut the sweetness and judicious use of the oriental chili sauce sambel oolek will provide both a chili kick and garlicky goodness.

Try adding lemon juice or mustard.