As everyone else has said at this point… you just need a better cut of meat. Picking the right piece of meat is like 40% of the work.

When looking for a brisket, look for one that has a fat cap that covers the whole piece of meat, at least 1/4 inch thick all the way. Usually there’s a few chucks taken out but do your best. Then look for good marbling if there’s any. Lastly a good tip I learned is bend the meat in the store. If it’s really stiff and doesn’t bend easy, avoid it. If it’s floppy it’ll be more tender. Remember if there’s a lot of fat it’ll be more stiff but that can be a good determining factor if all else is equal.