You are correct. All three of the vaccines (moderna, pfizer, J&J) instruct your cells to create spike protein. Moderna and pfizer do it by directly delivering the mRNA to your cell's mitochondria to make the spike protein (never goes into cell nucleus) while J&J uses the shell of an adenovirus (which they allegedly altered to prevent it from replicating) to go into your cell's nucleus to deliver the genetic material which causes it to produce the mRNA to instruct the mitochondria to create the spike protein. Same end result but different methods to achieve it. The all involve gene therapy.
You are correct. All three of the vaccines (moderna, pfizer, J&J) instruct your cells to create spike protein. Moderna and pfizer do it by directly delivering the mRNA to your cell's mitochondria to make the spike protein (never goes into cell nucleus) while J&J uses the shell of an adenovirus (which they allegedly altered to prevent it from replicating) to go into your cell's nucleus to deliver the genetic material which causes it to produce the mRNA to instruct the mitochondria to create the spike protein. Same end result but different methods to achieve it. The all involve gene therapy.