Ruling on Contradictions in the Torah

In a halachah where there is a contradiction between two places in the Torah (for example, a tithe according to the Laws of God that can be redeemed as a complete redemption with the addition of a fifth according to Korach for the priests and Levites, and according to Reh it must be brought to Jerusalem that can be redeemed temporarily without a fifth), is there any rule by which we can decide as one of them and is it possible to assume that there are several options for fulfilling the mitzvah, all of which are good, and is there a reason to follow the Yishuv of the Sages when we do not follow the main principle of their method (that the Torah is unified)?