The bridge tool does not work across the symmetry of a body. You'll have to clear the symmetry first, then bridge.
Afterwards you can turn on internal symmetry again.
However you are lucky that your model is even converting. There is actually too little geometry in your model and you'll need more edge loops to avoid the self intersections. the self intersections are not visible in smooth view mode, but in box view mode they are very apparent.
A rule of thumb is that if you have to pull vertices so far out in bas view mode that they stat intersecting and/or the box view model does not represent the geometry you are looking for then you need more edge loops.
@SaeedHamza the additional edge loops you deem unnecessary are there for edge definition. They are needed, but simply have been applied too early. This is one reason I rarely model T-Splines in Fusion 360, but in Blender. You cannot apply edge crease weights to help with the visualization o he final geometry.
You can only crease which often results in very undesirable effects if you continue to model with creased edges.