Cross-platform personal collection

I use the Gospel Library app on both an Android 10 tablet and a Windows 10 laptop (each has its own strengths, so I switch by situation). I have a custom collection on the tablet, but cannot seem to figure out syncing it to the laptop. Is that even doable?

Custom collections sync between iOS and Android Gospel Library when you're signed in with your Church Account, but the Windows app doesn't sync custom collections (Gospel Library Online also doesn't show custom collections). I think there's an in-app feedback link in Windows Gospel Library where you can send feature requests.

It wouldn't take the submission of feedback.