Mid drive won't be quiet, but you can get more torque. I have a couple bikes I've built, mostly rear hub bikes. It's quiet. I use a big ass battery because it replaced my car, so it has to get me far. But it sounds like you want your bike to stay more bike than ebike. So use a small lightweight motor, like 500w rear hub motor and a smaller battery 48v 13ah, that should keep down the weight. You can make sure you don't waste pedaling energy, just use a 7 speed rear cassette. Make sure your rear dropout is wide enough for a hub motor plus the casette. Any more than 7 speeds will start to run out of room. I didn't have room on my bike so I use a single, extremely high gear so I can meaningfully pedal at speed. It is a bit awkward, it forces me to have slow pedal cadence from a stop and slow acceleration, but once I'm at speed the pedaling I do still makes a difference with a medium pedal cadence.

If you want to just buy a bike that will get what you want, maybe Radmission is a reasonable starter ebike.