I remember hearing that either the Rambam or the Shulchan Aruch had a chapter/volume ("something daas") on common sense and the dos and don'ts of human interactions.
Is there a particular text I can look into to learn more about this topic?
I am not looking for halachah in particular but just wisdom and common sense on how to navigate life more smoothly via the use of the wisdom of the sages.
You are most likely thinking of the fifth volume of Shulchan Aruch, referenced e.g. in this tale:
A popular Jewish folktale tells of a young student who came to a prominent rabbi to be tested for ordination. The rabbi's first question was "Name the five volumes of the Shulkhan Arukh."
The student, thinking that the rabbi had made a slip of the tongue, named the four volumes, but the rabbi asked him to name the fifth.
"There is no fifth volume," the student said.
"There is indeed," the rabbi said. "Common sense is the fifth volume, and if you don't have it, all your rulings will be of no use, even if you know the other four volumes by heart."
This is not an actual physical volume, and indeed, the idea that there is an actual volume to study goes against the very idea of it. The idea is that one should develop and employ common sense, rather than abandoning it in favor of literal words on a printed page.
I think you are referring to Hilchot De'ot in Rambam's Mishneh Torah.
I don't agree with the belief that "common sense" is innate and that humanity is born with it. It has to be learned at a young age and needs constant refinement from multiple sources - parents, teachers, mentors, as well as proper reading and learning.
Pirkei Avot, as mentioned above is a good starting source, and I recommend Rabbeinu Yonah's commentary, in particular. Main reason- if you read a bit about his biography, he was one of the leaders that encouraged the massive burning of the works of Ramba"m. Later, he realized his horrible mistake, and made extremely sincere repentance. Among the penitent actions include his frequent mentioning of Ramba"m in his commentary as well as writing Sha'arei Teshuva - another terrific work of "common sense", as teshuva supports humility - an essential behavioral quality that is, I feel, NOT innate but needs to become "common sense". To me, when a person understands his own mistake, and not only repents, but corrects his own behavior and makes a huge difference in the world to teach this positive behavior to others - THAT impresses me as someone who "got it" and is a good example / mentor for teaching morality and wisdom.
Together with Pirkei Avot, I recommend delving in Mishlei - Proverbs. If anyone is able to deliver wisdom and "common sense", I don't think any human in the world can do it better than the Wise King Solomon.
How about Pirkei Avos in depth?
