I'm genuinely curious - what is this mindset supposed to accomplish?
However, we don't want to die (because we are so attached to life, it's hard to overrule billions of years of evolution).
So we have to endure the suffering until we die on our own, or until the suffering becomes great enough to overcome the mental barrier of suicide.
Just as we can train our bodies through exercise to deal with exertion, so too can we train our minds through philosophy to deal with suffering. It makes life easier to live.
(I say this having adopted some of these views and found myself at a lower baseline happiness, but also with less variance.)
Likewise death: when you've faced the prospect of death, of coming to grips with it, and survived it & now knowing you're on borrowed time, all things become a gift. I am literally hearing my heart beat right now from the sound of a machine, and every beat is directed by a computer; I've been (technically) dead, not for want of my body trying to get & stay there 4 different ways. Every moment is now a gift, something I'd not have experienced if not for modern medical tech (even healthier than most my age). Every dreary day, every hurtful word, every irritation, ... each is better than not having it at all, each being a painful step to the joys of sunsets, cardinals, smiling children, snuggling wife, and every other precious moment I have because "they're stopping his heart now" was followed (hours later) by the unreal experience of waking up.
For those who have not been to the edge and back, one's sense of proportion would do well to contemplate the meaning of going there, giving proper scale to the minutiae so many find impossibly grievous.
Does Stoicism rationalize suicide?
>But remember the principal thing, -that the door is open. Do not be more fearful than children; but as they, when the play dues not please them, say, " I will play no longer," so do you, in the same case, say, "I will play no longer," and go; but, if you stay, do not complain. [p. 1081]
A detailed analysis can be found here: https://people.creighton.edu/~wos87278/Stephens/Ancient-Phil...
Aurelius as such (Meditations, book V):
>As thou intendest to live when thou art gone out,...so it is in thy power to live here. But if men do not permit thee, then get away out of life, yet so as if thou wert suffering no harm. The house is smoky, and I quit it. Why dost thou think that this is any trouble? But so long as nothing of the kind drives me out, I remain, am free, and no man shall hinder me from doing what I choose; and I choose to do what is according to the nature of the rational and social animal.
(and in book X):
>For to continue to be such as thou hast hitherto been, and to be tom in pieces and defiled in such a life, is the character of a very stupid man and one overfond of his life, and like those half-devoured fighters with wild beasts, who though covered with wounds and gore, still intreat to be kept to the following day, though they will be exposed in the same state to the same claws and bites. Therefore fix thyself in the possession of [virtues]: and if thou art able to abide in them, abide as if thou wast removed to certain islands of the Happy. But if thou shalt perceive that thou fallest out of them and dost not maintain thy hold, go courageously into some nook where thou shalt maintain them, or even depart at once from life, not in passion, but with simplicity and freedom and modesty, after doing this one laudable thing at least in thy life, to have gone out of it thus.
In short: leaving life on one's own terms is fine, provided they are rationally considered (so not on the spur of a moment).