Lower your bar or arm pads to get a flatter back. From the position you show you could present less frontal area.
Can't tell from the pics but its usually more aero to move you forearms as close together as possible.
Both modifications take practice so that your muscles adapt to the constrained position.
Saddle height looks pretty good from the youtubes, perhaps saddle slightly back a little. Your patella looks a little forward of the pedal axel at 180 degree.
All the usual advice applies too, form fitting skin suit, disc rear low spoke count front, aero booties and the most important: concentration the whole time you are TTing. This is a must to get the best time possible. Good luck too