To OP,
1) Did MAD-DFW-SAN before, IB ticket, AA metal, non flex ticket. It was 2022 and immigration chaos was everywhere, I asked to be moved to the later DFW-SAN flight and IB obliged without re-repricing. I think the earlier LupineChemist recommendation of saying "you move slow" is good. IB+ elite team works by the book but they do have discretionary powers.
2) Any reason why you didn't want the return TATL leg to be on IB metal for EU261 protection?
3) the Amex insurance, is that the vanilla Plat one? Or you got exta. The Plat's insurance is not very good and might not even apply in your situation.
To others:
In the reverse scenario, so AA ticket IB metal, with an IB schedule change making the connection at MAD a tight (but within MCT), would AA change the ticket for free?