So generally speaking I don’t think extending life will take much resources once we figure out the biochemistry of it. If it does and that deprives others of their enjoyment of life, sure I get it, I will just work to make life extension cheaper. However frankly consumerism and an addiction to travel and tourism eats up a lot more resources than the research and production of high tech biotech etc.
If we end up with too much population, well I ask for nothing more than that my life is valued as much as the life of a baby, so long as I remain useful to society, don’t value someone’s right to have a child, more than my right to continue to live.