There is obviously only one single reaction force T to
the movement of the plane, however it is convenient
to split it into its two equivalent components Tx & Ty
which are acting at right angles to one another and
hence can be placed in opposition to the Thrust &
Weight components so as to balance in straight and
level unaccelerated flight.
To think that the three force model or four force
models are describing different things is to completely
miss the point.
-- Andrew