If there is anything I can do (including mental actions such as thinking dreaming or imagining) even in a very limited capacity then that is better than there being nothing at all. And if I am alive but cannot do anything at all then logically it is the same as death so taking measures to try to preserve life can only be neutral or helpful, they cannot make the situation worse.

Pain and suffering are just signals in the brain that only have the value that we give them. It's an alarm saying "something is wrong". Sometimes it's faulty. Sometimes it's right but you understand and yet it continues since natural selection built it and didn't think of that (since of course natural selection does not think). Sometimes you don't understand but you are not in a position to do anything about it though caregivers or doctors may or may not be.

And then as another point some people live with chronic pain disorders but are still quite capable of getting around and still live fulfilling meaningful lives.

Meaning does not come from pain or pleasure, mere physical sensations. Meaning comes from the actions we take using what ever it is we got and the values we choose to give to things (and this valuing is itself an action). Without action there can be no meaning. Without life there can be no more action unless there is an afterlife or reincarnation but there is no hard evidence suggesting there is. Supposing there were it's unlikely to be any different in duration or in your ability to act meaningfully within it just because you live longer so you might as well try to live as long as possible.

You can disagree but it's rather arrogant to assume that everyone inevitably arrives at your way of viewing the world or that doing so is a mark of maturity. Otherwise I'd love to have a rational logical discussion of our different views without insulting each other's maturity intelligence or character.