A German perspective: Households pay between $0.30 and $0.40 per kWh, Diesel is at around $1.60-$1.70/l and it is safe to assume 6l/100km for a Diesel car. I was never able to consistently drive an EV at < 20 kWh/100km, in Winter it's more 25kWH/100km for certain ones (I look at you Mercedes EQB) it was closer to 30kWH.
To account for the full cost of car ownership I can recommend the methodology of the ADAC (German Automobile Club, Germany only: https://assets.adac.de/Autodatenbank/Autokosten/autokostenue...).