OH! This is a new one on me…
After I closed VSCode then re-opened my project, I found my added STM32F103xE define entry was no longer there.
I tested it several times and could visually SEE the entry get removed every time.
EDIT0:
Except I guess formulahendry forked it because that setting isn’t available.
EDIT1:
Welp, looks like it’s intended to work that way and “build_flags” is what’s needed for any additions. Who knew… (that guy)