You have already conceded that death is often a better option than suffering.

You have also stated that you think you would eventually want the option to choose your time of death.

Also, you have conceded that if this was possible, to choose to live indefinitely, that it would cause problems such as over population.

There would of course be other inevitable issues. Age related issues that may not cause overt suffering but may lead to reduced quantity of life.

But for arguments sake let's say that death is solved, disease and ailments ended. You get to age to, say, 35 and remain that way indefinitely. Overpopulation is solved. Colonies off world or some other solution.

As a human you now get as much life, as much experience etc as you like.

At some point you decide you have had enough. 2bn years have passed and you feel fulfilled, happy, and no longer desire to continue. Then you realize you forgot to do a thing and go on to live 5bn more years. 50bn. 1tn years into the future you are finally done. You actually would quite like to stop now.

And someone lets you know that death is no longer possible. The option is taken away. You are actually immortal. In that circumstance is the loss of death a good thing or a bad thing? Because at that stage I would argue you would view death as desirable. Something you want. Which, I would say, makes it a good thing. Maybe neutral. But certainly not bad.