My biased opinions:
For Covid-19 vaccine guidelines, the most transparent governments are South Korea and Japan. Due to MOH's bias towards Pfizer & Moderna, our local press intentionally not clarifies that Sinovac and Sinopharm are acceptable boosters. If MOH don't recognize Sinovac or Sinopharm as boosters, China will probably ban all flights from Singapore.
If we have the luxury of time, newer vaccine-technologies such as Valneva and T-cell vaccines will offer safer and longer protections.
https://www.theguardian.com/society...covid-vaccine-that-could-give-longer-immunity
Moreover, vaccinations do not prevent us from COVID-19 infections. However, we are now forced to take boosters, therefore my personal take is to take the safest option, just to clock the mileage so that we will not lose our jobs.