From wikipedia:

In early 2002, Elon Musk started to look for staff for his company, soon to be named SpaceX. Musk approached five people for the initial positions at the fledgling company, including Michael Griffin, who declined the position of Chief Engineer,[17] Jim Cantrell and John Garvey (Cantrell and Garvey would later found the company Vector Launch), rocket engineer Tom Mueller, and Chris Thompson.

So your claim that

Some of those people founded spaceX - Elon didn’t start it, he came in when they were getting off the ground, just like with Tesla

conflicts with wikipedia’s history of the company.