And others with overall low rates have dumb utilities that charge high rates if you use more than 1000kwh, which most EV owners certainly do.
This is just like a gas car, where the conversation would start with mpg, not "What's your gas cost per month before and after getting gas car?" It is precisely because of the variation in both gas price and usage that it is important to start from consumption per mile and not a total price.
In general, EV owners are pretty savvy. More than most actually know what they pay per kwh and have a pretty good idea of their consumption. The biggest common mistake that I see is net vs gross.
I've got a Tesla Model 3. My wife had a Pacifica Plugin Hybrid. Any given point of the day, one of them is probably plugged in if we're at home.
It took 2-3 hours to recharge the Pacifica for it's 35 mile range. Full recharge on the Tesla is about 5 hours if it's totally drained but the Tesla has much better battery management so you typically set the maximum charge to 80% of the battery for daily driving. Typically, I'll plug the Tesla in when it's still got 50-60% of the battery left.
Looking at a graph of the usage at my house from the utility company is pretty hilly and coincides with weather. Goes up a lot during the hotter months as my AC kicks on. I don't notice anything significant from it though.
I'm also enrolled in a bill normalization program with my utility company where they give me the same bill every month throughout the year so that we don't get surprise spikes as the weather changes.