What do you think is the purpose of alien races like the Goa'uld, the Replicators and the Ori?

The Ori were a corruption of ascended beings, which were arguably artificially created by the desires of evolved species to be free from want and pain. The Goa'uld's main deviation from your standard parasyte/symbiote is their shared permanent memory across generations(a reasonable-enough adaptation, although an extremely unlikely/costly one versus our understanding of genetics/inheritance); From there, they learned how to use and re-purpose tech, and just as importantly, almost never had to re-learn any advancements they mastered.

Honestly the idea that the Goa'uld had to steal every bit of tech they used never sat right with me. Their healing capabilities reek of the sort of genetic engineering they alone benefit from, and no other species has such, so who did they supposedly steal it from?