My proposal is the following groupings (copied from Superlist)

Overdue - in place already and the behaviour to be the same

Today - instead of Current, as that's what it is

Tomorrow - instead of Upcoming, to make it clearer the window of time

This week - as the name suggests, to help with grouping

Later - as a catch all for everything in the future

Then everything with no due date stays organised by note name as it stands today. I have used this format for many months and it's very very simple to follow and makes complete sense.