"A Better Us" or "A better We"?
Solution 1:
Provide the appropriate transitive verb of your choice with the phrase as its object:
Build a better us
Behold a better us
Exercise makes a better us
But bear in mind that even as the complement of a copulative verb, we prefer the objective case when strict application of grammar rules requires the nominative. Must people would say
This is a better us
and not "a better we," just as they would say when the gang comes back
It's us.
instead of "It's we.