it's not like that at all.I dare say that when you go to your suppliers to negotiate you don't say. "By the way. I will take any price you give me. I won't bother trying anybody else". This seems to me to be your position on Brexit. Accept anything they are minded to offer.
If we want a transition period, they insist on us giving them a guarantee.
If Bojo wants only to leave without the NI backstop, he only has to convince our parliament, not the EU.
Our parliament will tell him to extend A50 to the end of 2020, that will give us enough time to prepare for a no deal.