We study avatars of T-duality within Sen's formalism for self-dual field strengths in various dimensions. This formalism is shown to naturally accommodate the T-duality relation between Type IIA/IIB theories when compactified on a circle without the need for imposing the self-duality constraint by hand, as is usually done. We also continue our study of this formalism on two-dimensional target spacetimes and initiate its study as a worldsheet theory. In particular, we show that Sen's action provides a natural worldsheet-based understanding of twisted and asymmetrically twisted strings. Finally, we show that the $\mathrm{T}\bar{\mathrm{T}}$-deformed theory of left- and right-chiral bosons described in Sen's formalism possesses a scaling limit that is related via field-theoretic T-duality to a recently studied integrable deformation of quantum mechanics.
