All of the same steps were completed, but many were completed concurrently to get the job done faster without skipping any steps.
"Long term study" is a red herring. The safety and efficacy of COVID-19 vaccines has been firmly established.
No vaccine ever has had side effects that don't appear until long after vaccination, and there is no coherent scientific explanation about how that could be possible now, including with mRNA vaccines.
The COVID-19 vaccines have been injected BILLIONS of times over the course of more than two years with few signs of serious side effects.