Brisket does not taste like steak, it should not taste like pot roast, unless you want pot roast, in which case, it makes a tasty pot roast.
If you must stick to flats, try and find a flat with a fat cap, that is a big help. Salt and pepper is fine, even preferred by some. I do not foil, I wrap in butcher paper, I do put a splash or two of liquid into the paper. I fold the paper up loosely and put back into the pit.
Foil or panning runs the risk of steaming or creating the 'pot roast' taste. No wrap or paper reduces that risk.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"I'm Armenian...perhaps...but then again...maybe not..."