To rule according to the rules or explanation

However, we have often found the first ones who ruled against the Talmudic rules (for example, the Rambam ruled that the Abiyyah is beyond Ya'el Kagam - "You shall not work, you shall not gather together, and so on").

What is the Rambam's Pasha really?

Certainly not a sweeping attitude towards the rules, as the Gemara itself does.

I suppose. There are other examples and not just the Rambam. In my opinion, when they were convinced of one side's argument or when they found a contradictory issue, they made up their minds to rule as the other side.

I once wrote that all the rules of jurisprudence are instructions on what to do when we have no decision of our own. But when we have our own position, there is no need to resort to rules. See, for example, my article on autonomy in relation to the rule of following the majority or doubting the merits.

Rabbi Michi, how can one establish a halachic position that is not in accordance with the rules?

With common sense. How were the rules themselves created? Reason usually stands on its own and is not based on a rule. And the late Wittgenstein already stated that the illusion of acting according to rules is a facade, and in fact intuitions sit behind it (in his discussion of following a rule).