Re: I'm not sure.
Parliament is either sovereign or it isn't.
I understand your concern (even though I don't share it). I am no expert, however my understanding is that Parliament is still sovereign. I believe Parliament can repeal the Human Rights Act, and abrogate any treaties it likes, any time it likes. At which point, the judiciary will no longer be testing legislation against human rights.
Of course, the fallout would be immense. It would involve leaving not just the EU but probably much of the civilised world. Judges might resign. It is also possible that the Queen would consider refusing to allow it, prompting a constitutional crisis. But, if I understand correctly, Parliament is still sovereign. Parliament has chosen to hamstring itself, and it could, in principle, choose to cut those strings.
If there are concerns over the sovereignty of Parliament, the answer most definitely is not to hand powers to Theresa May instead!