I am looking forward to get everybody else vaccinated before I am getting 3rd dose.

Any dose is best spent vaccinating an unvaccinated person, even if looking from a purely selfish point of view of already vaccinated population.

There is also still a lot of people that can't get the vaccine in less developed countries.

Unfortunately it doesnt work that way - the infrustructure required for the mass production doses (pfizer, moderna) is pretty huge and third doses will be avilable in most regions long before 'everybody else' has the proper infrustructure in place. For this, it isnt purely zero sum.

I’ll die before getting the injection

Yes. For those at risk, a booster seems like an excellent idea. Hopefully there aren’t any downsides to widespread rollout. Downsides being ade or the increase in vaccine evasive variants. For the latter of those I am more concerned about waning efficacy than a booster, but who knows. It’s all one big messy experiment.