Catch Stephen Strange never giving him the funds he needs to do either of the B things lest they disrupt the status quo.

I'm not sure what you guys have landed on re: the Tony/Nat/Bucky situation but if it's still that Tony's informed and okay with it, maybe Stephen's been funding Tony's work on increasing efficiency for a while but going nowhere on the other lines of research then on Tony's 99th request for more funding for other things Stephen straight up gives him the "either you handle your magpie or I'm cutting you off completely"

Starts playing Nat and Tony both from different angles as a means of not having to deal with blatant corruption at the highest levels of power

Also regardless of what we end up doing he's going to exclusively call him Anthony (because he's had a Thing with comics Tony for a few hundred years and doesn't appreciate these whippersnappers with their hand me down names) and if Tony so many as dares to call him out on it he's putting him in the bin