Mid Drive Conversion or Buy a Separate Pre-Built eBike? Already have a good bike...

Thanks ahead of time for hearing my situation out and helping me as a noob to e-biking. I have been researching and am having a hard time deciding whether to buy a e-bike, or convert mine to a mid drive system of sorts.

I currently have a Niner RLT9 Steel 3 Star Rival build, reference: RLT 9...