I've had double vaccinations. The Russian vaccine is perhaps one of the most underrated vaccine as it is two in one, an RNA and Vector
so both do the same job differently. What one misses the other hopefully covers.
You can achieve the same by say
getting your two shots of Phizer,
waiting a few months then gett AstraZenica
Then six months later, get what ever vaccine that is made for the new varients.
From the people I've spoken to and my own experience, the first shot rarely has a reaction,
its the 2nd shot that gives you body a wake up call to fight covid.
A good reaction to the 2nd shot is a good thing.
With the Astra Zenica, I got 36 hours of aches and pains, no temperature increase like the 2nd shot of Phizer.
Where I am, no one wears a mask and it has a much lower rate of new cases than most other places with requirements etc.
Land of the free and brave as they say.