Question: While the rabbanan did not rescind the issur of removing bread, in the case where it was placed in the oven on shabbos despite it leading to an issur doraisa. What should one who finds themselves in this situation do? Wouldn't it make more sense for the individual to remove the bread and be over a derabbanan rather than follow the dictate of chazal and be over a doraissa?
Good question. TOSFOS (4a, DH Kodem she'Yavo) explains that if one leaves the dough to bake because the Rabanan forbade him to remove it, it is considered an Ones (an unintentional transgression beyond one's control), and he would not be Chayav Misah for the baking, even if he initially placed the dough in the oven on purpose. According to this, we may answer your question by saying that an unintentional, unavoidable transgression of a d'Oraisa is indeed less severe than an intentional, purposeful transgression of a d'Rabanan.