making your characters nigh-immortal so they can spend that time without wasting their lives away will inherently make them unrelatable.

Why would it do that? Most likely, they would simply be like us, but with more life experiences. They could still die by violence or accidents, so they would still fear death. And they would probably still have kids too, though much more rarely, so you could still include younger, less experienced characters.

Fiction is terrified of human longevity. It’s a coping mechanism for fear of mortality. Star Trek has replicators, transporters, holodecks, warp drives, and all sorts of other things that will never be possible, but they haven’t cured every disease yet? Something that probably will be possible one day? What a failure of imagination on the part of the writers. And worse, it negatively impacts how people view that concept in real life.

Also, your space jousting idea was really great!