Is it true that the only “immunity” given with the Covid vaccine is to its manufacturers ?

No the first dose gives you over 60% and after two doses your immunity rises to over 80%.

This is standard for most vaccines for example "Take the MMR – measles, mumps and rubella – vaccine, which is given to babies around the world to prevent these deadly childhood infections. Around 40% of people who have received just one dose are not protected from all three viruses, compared to 4% of those who have had their second. People in the former group are four times more likely to catch measles than those in the latter – and there have been outbreaks in places where a high proportion of people have not completed the full MMR vaccination schedule"

Which is why it is also essential to bring down the infection rate at the same time.

Vaccinations during my lifetime have saved millions, probably billions of lives around the world, the evidence is there for all to see.  Maybe you should try reading some of it, written by people who actually have training and experience in the subject they are talking about.  A few links below which you could look at rather than wherever you are getting this idea from.

https://www.bbc.com/future/article/20210114-covid-...

https://www.historyofvaccines.org/timeline/all

https://www.historyofvaccines.org/

https://www.nfid.org/immunization/vaccine-science-...

https://www.nationalgeographic.org/article/strange...

https://www.weforum.org/agenda/2020/04/how-vaccine...