My advice (I am an MD): take whatever you can get and don't rely on promises. Sinovac was the first vaccine to be developed, long trusted old school technology, and although the protection may be less than than that of other more sexier (mRNA) vaccines it certainly helps to get you less ill, avoid ICU and a graveyard. The rich countries are reaching the point of not needing as many, the companies will keep producing, so my guess is that the market will be flooded with many different vaccines. Next year you can upgrade your immune status with something else, I am sure.