You did a great job.

Hello Rabbi
In the Mishnah of Baba Metzia 44: It is written, “Rabbi Tarfon in Lod ordered the deception…. And the men of Lod rejoiced. He told them that they were allowed to return all day. They said to him, ‘Rabbi Tarfon will leave us in our place.'”
My question is: Why couldn’t the Lod judges rule like Rabbi Tarfon only in the matter of fraud, but in the matter of return, follow the method of the Sages? And if there is one rule that they follow in the opinion of Rabbi Tarfon, then they should follow it in all other matters?
Indeed, in the Gemara (Rosh Hashanah 14:14 and more) it is stated that one may follow the voice of Beit Shammai and the voice of Beit Hillel, but only if it contradicts the same halakha (such as impurity in the bones, etc.) and only then is it forbidden to follow the voice of one and the voice of the other.
Apparently, in the matter of Didan, there is no contradiction if one follows Rabbi Tarfon on one issue and the sages on the other.
And to expand the question: Is there such a thing as “having a rabbi” where you are obligated to follow in everything according to one rabbi?
The Talmud is apparently full of deeds that prove otherwise (for example: Blessings 44: “A rabbi said, ‘Let him be put to death…all the disciples of a rabbi who say, ‘I am not put to death'”), and on the other hand, sometimes there is a meaning in the Gemara, since there is an obligation to follow a particular rabbi (see Gemara Shabbat 37: “…a donkey that is close to a rabbi and Shmuel will serve him like a rabbi and Shmuel, but I will serve him like Rabbi Yochanan…” and some consideration should be given to the fact that they are close to a rabbi and Shmuel…)
Thanks in advance.