Absolute noob to ebikes, wanting to convert a trek marlin 7

I have a trek marlin 7, would like to convert it to something with a fair bit of pull that can do 30mph+. I appreciate how subjective this is, it goes on gradient, weight of the bike, weight of me etc. but basically one that packs a little bit more of a punch than a little bit of pedal assist.

Few questions (the questions themselves may be bad/wrong, feel free to correct):

- How can I choose between mid/rear drive options?

- Depending on the answer to the above, which is the product people would be more likely to recommend to someone who is (generally) handy with DIY but doesn't know a thing about bike maintenance/repair?

Thanks a LOT in advance!