Looks to me like when the bobbin case latch screw (the one the manual says not to loosen) was loosened then retightened, the thread gap was set wrong. The manual says .010" to .015" between the heal of the bobbin case and the spring. Use a narrow gap gauge held vertically between the two.
The crooked feeding could be because of the ZZ foot. Try a correct straight stitch foot on it.
Joe