You’re right, it’s only roughly one in every 20 rolls. It’s only almost precisely one in every 20 rolls. It’s only a 5% chance, which some would say is literally synonymous with “one in every 20 rolls,” which isn’t strictly true, because it’s possible to have more or less than one natural 20 in any run of 20 rolls, because it’s only one in every 20 rolls on average.

Glad we can agree.