If you are commuting, you can basically close your eyes and pick any e-bike or conversion, hub drive or mid-drive, pavement is so easy with electric power you can't go wrong. Just make sure it's both throttle and pedal-assist, a lot of the cheapest ones are throttle only (for hub drives). 250W is plenty on pavement, maybe for your weight 500W but the battery and motor is less than $1000 together. Almost any bike can be converted, especially mountain bikes. Bafang has many different configurations, and even offers cassette-based freehubs on their rear hub motors. Some people say a mid-drive isn't great on pavement but others on here are free to chime in about that issue.
The bike, motor, and battery is the easy part, the harder part is deciding if you can do the whole DIY yourself or if you need to have a bike shop help. That can get pricey and they don't always do a great job. The last time I did a conversion it ran around $500 and they didn't even hook up the wiring. I ended up finishing it in my garage and besides the PAS sensor, I didn't even need their help after all. So you really need to do your homework on bike shops and call around a lot if you are not mechanically inclined.