After about 3 hours of driving, you’re going to be ready for a break. At 70mph, that’s 210 miles.
Batteries tend to charge quicker in the first 80% than the last 20%, and also don’t charge quickly in the last 10%, so add an additional 30%.
Add another 20% for cold days. There are a few odd days of extremely cold weather where it’d be lower, but this is rare anywhere people actually live. Long range traveling on those days is also highly discouraged regardless of the type of car. Or even short range traveling, for that matter.
We do not need to hold back the rest of society just because a handful of people live in the arctic circle.
Add all that together, and you get to about 330 miles. This is enough to get you to 80% charge at each stop, likely within 30 minutes. Maybe even 20. Just right for a food and bathroom break that you’re going to want, anyway.
If you think the number should be 4 hours of driving rather than 3, then 440 miles is the number to shoot for.
Current electric cars are about there already. Further battery advancement can go towards making the cars lighter and cheaper, not pushing range to unnecessary distance.