The first thing to check is that we are not reading the principle too quickly, but actually reading it and absorbing the detail that’s written.
Working software is the primary measure of progress
Have you ever been privy to an argument about the difference between a milestone and stage-gate? This was project management in the 1990s. Managers would spend time calculating when 50% of the project was done by the activities being completed, even when nothing was delivered.
Stop seeing task completion as actual value. That might be the only goal of the principle but it is super important, just stop measuring all the other stuff as progress.
Still the liner project timeline and the management's insistent need for predictability kills any hope for this principle. Then again, teams have to try harder to deliver more frequently as its often the lack of measures that leads to the management's insecurities. It's easy to spot failures to adopt this principle.
Any discovery milestones
Showcases about progress
Big bang delivery
Try measuring outcomes not activity it will improve customer satisfaction.