If there is a question here, other than a couple of rhetorical ones, I find it difficult to locate it. You seem to have a fairly good grasp of how you feel about the "Do."
When I was a young student, many decades ago, all of the high ranking Black Belts and Masters would say to us that "Do means the 'art,' the 'way,' or the 'path'." As I advanced over the years, I came to believe that they used the wrong conjunction. I teach my students that "Do means the Art, the Way, and the Path."
The Art of living, learning to enjoy, appreciate, and value life. Stop to smell the roses - - protect the weak and innocent - - don't kill unjustly.
The Way of being in harmony with nature. Choose compromise over conflict - - use force only to prevent a greater harm or injustice - - Don't try to stop the falling tree, but merely step out of the way - - in order to avoid drowning, don't swim up stream - - don't spit into the wind.
The Path of right behavior. Develop within yourself a good moral compass, and a sense for right and wrong, then choose right. Associate yourself with others who choose right over wrong. Accept the consequences of your actions, and avoid repeating mistakes in poor judgment. Temptation is the slipperiest slope on both sides of the Path of right behavior.... avoid it at all costs.
As for the Tenets of Taekwondo, they will vary from one organization to the next. A Tenet is a doctrine, or belief in something that one holds to be true, usually suggested or required by an organization, and often self imposed. In Taekwondo, they are guidelines of behavior or rules of conduct in everyday life. When I was in the Boy Scouts, they taught us to live by the "Scout Law" which contained twelve parts (or 12 tenets).
"A scout is: Trustworthy, Loyal, Helpful, Friendly, Courteous, Kind, Obedient, Cheerful, Thrifty, Brave, Clean, and Reverent."
I think that most of those could be summed up in the Tenets of Courtesy and Integrity, but I think a lot of people don't really know what those two words really mean, and even fewer live by them.
I go by the Following Five Tenets of Taekwondo:
Courtesy
Integrity
Perseverance
Self Control
Indomitable Spirit
The first one teaches us how to behave toward others (including respect, honesty, humility, and compassion), and to always do the right thing - - to do otherwise would be discourteous. The second one provides the strength of character to resist temptation, which would cause you to falter on the first tenet. The third tenet keeps us going with a resolve and determination to accomplish our goals, and finish what we started. The fourth tenet suggests precision, restraint, dominion over, and thus responsibility for our actions. The fifth tenet reminds us to remain cheerful and pleasant which will make the journey more enjoyable for yourself, and those around you. It also implies the unbeatable nature of one who relies on the strength of their Spirit. In other words, "it is not so much the size of the dog in the fight, as the size of the fight in the dog."

Respectfully,
Chief Master Eisenhart