I switched to a traeger a few months back, and I do love it, everything I’ve smoked on it has been outstanding, right down to bratwurst and Italian sausages.
but......... for big, hearty, fatty slabs of red meat, like a brisket, much like there’s no replacement for displacement, you just can’t replicate big chunks of hardwood for smoking.
It’s not very big, and would just barely meet your needs of doing two whole packers at once, but the biggest Weber Smokey Mountain would fit the bill. I loved mine, still pretty sad I got rid of it. It kept an even temp, didn’t use a ton of fuel, and cooked evenly. My sliced brisket and burnt ends always turned out perfect on it.