The fact that we have different information is understandable - everyone (even the most supposedly competent specialists and organizations) change their minds very quickly these days. Even to remember about masks - WHO has changed its opinion several times about whether they are needed or not. As for vaccines, in my country the "vaccine" SputnikV was first presented as a vaccine providing lifelong immunity, then the period was gradually reduced and now it is officially announced that after some time (presumably 6 months) revaccination will be required.
There are two factors in play here. First of all, immunity provided by the vaccine may last somewhere between 12 to 60 months. So you need to get vaccinated after this period. Now it is up to the government to decide whether you need a booster shot after 12 months, or 60 months (or some duration in between).
And now the second factor is the emergence of mutated strains. Current bunch of vaccines are showing limited efficacy against these strains. Some of the vaccine manufacturers have already created specific booster shots against the mutated strains. If you want full protection, then you need to take these shots.
I think that the presence of mutations makes vaccination meaningless. The situation is similar with influenza - vaccination is required for each strain. But given the riskiness of the covid vaccine and the potential side effects, I prefer to rely on natural immunity.
Those vaccines got different immunity and effect on the people that will take the shot. As long as there's going to be an immunity that will happen after the shot then it shall help to create herd immunity that's needed by every population by the world.
Some countries have already taken that immunity because most of their citizens were already vaccinated.
But nevertheless, infections occur even in those countries where the inhabitants are almost all vaccinated (Israel for example), and if we wait a few more generations of mutations, then I am sure the benefits of the vaccine will be generally zero.