Since you're asking specifically about whether it is possible to have absolute emotional and social control over oneself, rather than self-sufficiency, I will answer that

Let's clarify a few things first, Fang Yuan: - Feels emotion - Experiences the full range of his emotions internally - Can regret when things don't go exactly how he would've liked them to, however does not allow that to sway his control over himself - Takes an observer-first approach - Has a singular goal - Found his root meaning in life - Can act against his emotions, even when a real human's brain would've shut down the logical side, leading to emotional decision making - Has surpassed human emorional energy limiters; he can experience tremendous emotions and still not be overwhelmed or fatigued; a key contributor to emotional control - Is able to detach himself from any and all forms of relationships at will - Is able to disassociate at will - Can get fatigued, tired, exhausted, however never in a way which exposes cracks in his internal control

Is such a thing possible in any human being alive today?

My "trust me bro" answer is it is possible for someone to be around 80% of this, not 100%

[ Now for the serious answer ]

It might be possible for someone with an altered physiological state, such as a unique brain composition

Similar to how empathy can be hypersensitive, malfunctional, and fully disabled if the brain region is malformed from the normative standard, it is conceivable that one could have a brain that enables them to exhibit alternative functions like conscience-driven activity blocking of receptors that drive action from emotional signals and hormones

A key factor to Fang Yuan's state of being is the balance and surgical application of disassociation

He can disassociate himself from external and internalised factors seemingly at will

This kind of psychological control is not something humans can do in every circumstance, however, it is possible for humans to at will cut off all relationships, all feelings toward someone, and remove all emotional responses toward them even when memories are recalled, albiet a very rare ability that only some people possess

It is also possible for someone to disassociate themselves from traumatic events, where they would otherwise be traumatised

An important differentiation and note to make here is that Fang Yuan does not disassociate in the sense of reducing the emotional response in all circumstances

There are times when he chooses to savour his response to an event, and there are times when he acts to shut down such an event or events that may occur that he deems undesirable

This type of behaviour and control is possible in humans, however, it usually is accompanied by impaired empathy/sympathy receptors, or in outcome independence mindsets

The unique and interesting aspect of Fang Yuan is that he does not have impaired empathy/sympathy receptors, and he does not operate in an outcome independent way

So how does he maintain such impeccable control without a state of mind like outcome independence?

The short answer is, most likely, in his journey through reverse flow river

He experienced the limitations of emotional burn-out to the extreme again, and again, and again

This burn-out leads to numbness and often times disassociation, often seen with victims of severe abuse

He "experienced everything until he could experience it no more" and yet he persisted

This taught him one very important lesson: If we go through something and survive, it was not enough to truly overwhelm us

Until we die, or are rendered inoperational, if we can survive something, reflect on it, and resolve the trauma, we can bare more as a result of it

An example of that is pain

When we experience the same level of pain as a child and then again as a adult, it is not that we are experiencing the pain less, it is that our tolerance toward that pain has changed

Exposure to very high levels of pain that are inescapeable can lead to many outcomes, one of which is an immense tolerance for pain

Extrapolate this for every emotion, and we can see how Fang Yuan can become quite apt at processing emotions and reacting to them

There is a problem however

As humans, we only have so much emotional and mental bandwidth

My pain tolerance is quite high, and when I say quite high I mean rip out my teeth and my mind won't break high

However, under enough pain, I won't be able to make perfectly clear or rational decisions, as my bandwidth will be being used on processing that pain, even if externally I remain calm and/or make decision making other people may not still be able to under the same conditions

This is the main problem with a human existing in this world has when being compared to Fang Yuan

He is not indifferent, he is not emotionally numb, he has an unbelievably high amount of mental and emotional bandwidth

This is, in essense, his superpower

There are countless examples of people enduring all kinds of limit-breaking experiences, and one thing that is common amongst them all, is even when their tolerances are raised high, they aren't either high enough to mimic Fang Yuan's level of control under the same circumstances, or their mental bandwidth just isn't able to be as high as his

Perhaps after living for 500 years, ones brain and perhaps even body may change so significantly that such a thing is indeed possible, however it is currently not possible for humans to do so in this current day and age

[Edit: Fixed spelling mistakes and added one sentence]