I’ve checked your project, everything is correct. There is a delay of two bits in the sequence as shown in the image attached. Please place a View Signal Visualizer as shown in the image and check the bits. Move two bits at the RX output and compare the bits. They match very well and that is why you have very good QF and BER.
By the way, you don’t need to use the Matlab component because the View Signal Visualizer does the job.