Big Pharma may be evil, but they sure like cash, and they get a lot more cash from developing a safe vaccine than an unsafe one. Look at the J&J vaccine that the CDC is specifically saying to not get if you have Pfizer/Moderna available due to the risk of blood clots.
Dangerous vaccines don't sell.
The data regarding their vaccine safety is all readily available and not kept secret? https://www.msn.com/en-us/news/us/critics-outraged-by-fda-re...
The companies behind making these are legally accountable for damages if they do harm you, yes? https://www.cnbc.com/2020/12/16/covid-vaccine-side-effects-c...
And these are reputable companies that we can trust? https://abcnews.go.com/Business/pfizer-fined-23-billion-ille...
I just picked Pfizer fro these examples, but please let me know if you want one for Johnson and Johnson (and I'll be happy to provide).
If everybody is mandated to take one and they're immune to liability, they can make it as dangerous as they want as long as it's less dangerous than the other vaccines.