Does the app detect walking (and unlock Portmanteaus) if screen lock is on?
Will walking be detected if the phone is locked? What if the phone is unlocked, but the App is not in the foreground?
Answers for Pokemon suggest "No" for both questions.
Solution 1:
It doesn't appear that way.
In Pokemon Go, there is a setting called Adventure Sync:
Which allows you to link to your phones health data and collect walking distance while the app isn't open.
However, in Wizards Unite, this setting doesn't exist.
Doing a quick google search for "Wizards Unite Adventure Sync" you can see a lot of posts where people want this feature. Let's all hope it comes soon!