Post-orchiectomy and SRS, transwomen actually have LESS T relative to ciswomen because the latter also secrete T from their ovaries in addition to the adrenal glands while we only have adrenal glands. Some may need to supplement with extra T (like me) because T is too low, or not. It depends.
T is quickly knocked way down post-op (within 24-48 hours) and it is rare that more T is temporarily produced (due to stress and adrenal gland overdrive). What seems to occur more likely is that in those taking anti-androgens pre-op, when anti-androgens are stopped, androgen receptors remain temporarily more sensitive so react more strongly to even low levels of T and DHT. It's temporary and will settle within months, usually.