Do you like BBQ beef? That is one way to reheat and sauce at same time.
I do, and one of the things I am buying semi-regularly at the moment is a particular store's (M&S) "Pit Beans with BBQ Beef". I usually avoid commercial BBQ foods, which are often inauthentic, but this is really good. So that approach came to mind, but I decided I'd want to experiment and learn with that before taking it to friends.
Having said that, I have a small (1.2kg) brined brisket coming on Tuesday, which I intend to try and turn into a kind of pastrami. Also a proper Boston butt, which is difficult to get here. You can get pork shoulder, but it is usually rolled, and even if not will not be the same joint as you all know. This is because British butchers use different cuts to American butchers (and French, for that matter).
As a local butcher explained to me, they are capable of copying the American cuts, but that would affect the other cuts of meat around it, which they also need to sell. So I've found that the best way to get cuts as described in my recipe books is to use a specialist butcher, online. It is not particularly expensive, for a quality product; it just means good planning.
(We have a British cut here, called a "blade" or "blade shoulder" which is the butt with a big roast taken out of the top. That works fine for pulled pork, but usually it is turned into rolled joints, which the butchers love.)
Then at the end of the month, I have a brisket point coming from another online butcher, so I am not going to be hard up for brisket to experiment on.
Apart from (hot) grilling meats, one thing my friends know me for is my pulled pork. It is something I can now do in my sleep, and I am happy with my process. I have never got that practised in brisket, and have said many times I need to buckle down and get it right. So 2021 is going to be the year of the brisket.