Some of the other questions that you refer have been disspelled in their related discussions. There seems to be some carry over confusion but I am gonig to focus on main question you are posing.
I can see a possible hole in that you mix what "your" possible expriences might be with the possibility that other view points existing. That is if other have qualia they are not your qualia. There are actuallky arguments about how a computers state can only be based on information that has physical access to it. Combined with relativity that means that indeed computers percieve time subjectively. You raised this as a lack of imagination/lack of suggestions issue. If you don't find these claims compelling that is a separate concern of validity.
If the question of subjective observing can be rephrased as "does computation ever end?" The answer will be prettty much no, althought "human-like" computation might come to a permanent end.
Also even at the risk of being corny "What is an ocean but a multitude of drops?". That these moments will be lost in time as "tears in the rain" doesn't mean that they are not kickass moments.
Also if the "new" conciousness doesn't have psychological connection why the need for time dependence? Why can't the new the conciousness start while the old one is running? As in why would suicide have any impact for an unrelated counciousness start? If you take your viewpoint and arguments seriously you should be worried that you migth live lifes as the other you are currently interacting with. This can be potentially be more emphatethic viewpoint as in effect you live as everyone and makes altruism a form of egoism. But this risks blurring the line between you (r current incarnation) and others.
If you don't seriously believe that you could experience later other peoples qualia and the issue is "time doesn't work like that", then you might be positing a strange feeler that "snaps" into different viewpoints. What is this entity like when it is not snapped to anything? Why is it still subject to strict chronology if it doesn't have physical parts? You are mixing up a subjective time and ontological time. Your capabability to receive qualia will not have ontological inertia after your subjective time has come to an end. There is a realted question of of "terrible lives might be possible, how do we avoid them from happening?" but I am reading that you are posing a question of "how do I avoid for it to happening to me". A terrible life will happen obvoiusly happen to the person that borns intot hat unfornate position, but for most resonable defintions it can't be you.
This question has been bothering me for a while now, but I have the nagging feeling that I'm missing something big and that the reasoning is flawed in a very significant way. I'm not well read in philosophy at all, and I'd be really surprised if this particular problem hasn't been addressed many times by more enlightened minds. Please don't hesitate to give reading suggestions if you know more. I don't even know where to start learning about such questions. I have tried the search bar but have failed to find a discussion around this specific topic.
I'll try and explain my train of thought as best as I can but I am not familiar with formal reasoning, so bear with me! (English is not my first language, either)
Based on the information and sensations currently available, I am stuck in a specific point of view and experience specific qualia. So far, it's the only thing that has been available to me; it is the entirety of my reality. I don't know if the cogito ergo sum is well received on Less Wrong, but it seems on the face of it to be a compelling argument for my own existence at least.
Let's assume that there are other conscious beings who "exist" in a similar way, and thus other possible qualia. If we don't assume this, doesn't it mean that we are in a dead end and no further argument is possible? Similar to what happens if there is no free will and thus nothing matters since no change is possible? Again, I am not certain about this reasoning but I can't see the flaw so far.
There doesn't seem to be any reason why I should be experiencing these specific qualia instead of others, that I "popped into existence" as this specific consciousness instead of another, or that I perceive time subjectively. According to what I know, the qualia will probably stop completely at some subjective point in time and I will cease to exist. The qualia are likely to be tied to a physical state of matter (for example colorblindness due to different cells in the eyes) and once the matter does not "function" or is altered, the qualia are gone. It would seem that there could be a link between the subjective and some sort of objective reality, if there is indeed such a thing.
On a side note, I think it's safe to ignore theism and all mentions of a pleasurable afterlife of some sort. I suppose most people on this site have debated this to death elsewhere and there's no real point in bringing it up again. I personally think it's not an adequate solution to this problem.
Based on what I know, and that qualia occur, what is the probability (if any) that I will pop into existence again and again, and experience different qualia each time, with no subjectively perceivable connection with the "previous" consciousness? If it has happened once, if a subjective observer has emerged out of nothing at some point, and is currently observing subjectively (as I think is happening to me), does the subjective observing ever end?
I know it sounds an awful lot like mysticism and reincarnation, but since I am currently existing and observing in a subjective way (or at least I think I am), how can I be certain that it will ever stop?
The only reason why this question matters at all is because suffering is not only possible but quite frequent according to my subjective experience and my intuition of what other possible observers might be experiencing if they do exist in the same way I do. If there were no painful qualia, or no qualia at all, nothing would really matter since there would be no change needed and no concept of suffering. I don't know how to define suffering, but I think it is a valid concept and is contained in qualia, based on my limited subjectivity.
This leads to a second, more disturbing question : does suffering have a limit or is it infinite? Is there a non zero probability to enter into existence as a being that experiences potentially infinite suffering, similar to the main character in I have no mouth and I must scream? Is there no way out of existence? If the answer is no, then how would it be possible to lead a rational life, seeing as it would be a single drop in an infinite ocean?
On a more positive note, this reasoning can serve as a strong deterrent to suicide, since it would be rationally better to prolong your current and familiar existence than to potentially enter a less fortunate one with no way to predict what might happen.
Sadly, these thoughts have shown to be a significant threat to motivation and morale. I feel stuck in this logic and can't see a way out at the moment. If you can identify a flaw here, or know of a solution, then I eagerly await your reply.
kind regards