E-bikes still have a massive carbon footprint compared to regular bicycles

Don't let perfect be the enemy of good. If you'd prefer to use a purely pedel bike go right ahead, but I find having a boost for heavy loads and hills makes biking preferable in situations it otherwise wouldn't be. My battery is a 0.8kwh battery, which is more or less 15 iPhone batteries strapped together. My car is a 65kwh battery, literally 100x bigger for only 10x the range. While hard to find info, my understanding is my car is one of the more efficient ones out there too.

battery efficiency

Never comes into play, my bike has a 40km range with no load and no pedaling so typically even in winter the battery is far bigger than most trips I would take. There is also a longer range option (I think 100km) and you can quick swap the batteries if you really wanted to marathon. I do take the battery inside in winter as starting it warm does help it alot. I probably would be more hesitant to take heavy things in particular if I didn't have the battery.

Either way, a car, even if its an EV, will be the better pick for every situation I stated above.

Well no, if you look at my comment I do own a car (bolt euv). I literally couldnt take the fridge in the car, i had to go home and grab my bike which could carry it. I use my bike because my city has good infrastructure that makes it quicker than driving. No need to hunt for parking, and the exercise is nice. Being able to use it while lightly intoxicated is also a plus.