I didn't know you already purchased the 3k watt motor, maybe you can return it for a refund?
May not be something to consider but durability, practicality & utility are very much priorities for me on most bicycles or e-bikes as I get older.
Speed is fun, but in my riding area; there is not a lot of roads that allow me to sustain the high speed without getting to a traffic light, stop sign or other vehicle traffic.
On the bike trails, I can ride without concern of motor vehicle traffic, but there are walkers, runners, fishermen, families with kids, etc.. may not be the ideal place for high speed cruising.
This may be a little out of the price range, but it's something that's well designed for urban e-bike usage: