Telomeres are just the cell's odometer. Sure, rolling it back is good assuming that it extends the lifespan of the cell, but it still has the dents and dings it's picked up along the way from radiation & pollution, free radicals and oxidation.

This seems like part of the puzzle. First repair the damage, then extend the time span, and the more you do this the more opportunities you have to find an optimal solution.

I think the only thing that will actually work is for entirely new bodies to be built and for our minds to be copied over.

It's not immortality but that is probably as close as we will get, and once we can do that then extending our current body's lifespan will be exponentially easier.