Seems like PZ has now resorted to blocking the app install itself on devices running custom ROMs as it's no longer available in the Play Store. Sideloading the apk isn't useful as the app doesn't work if installed from anywhere( like Aurora) other than the Play Store. I have faced this issue in case of apps like Freecharge over the years randomly but sideloading the apk was a quick fix and later the apps became available on the Play Store.
Edit: Managed to workaround this issue. Even in Work Profile.
mine's not rooted and still shows that error - RIP
Ok - I was able to Payzapp work. Finally! Not sure what specifically worked as did too many tweaks.
What all I did (summary)
Removed Data & Cache and then Uninstalled Payzapp
Rebooted
Installed Payzapp (but didn't open it)
Added it to MagiskHide (double checked and selected all 3 activities)
Added to XPosed for XPrivacy, IAMNotADeveloper
Under XPrivacyLua disabled access to analytics, activities, installed apps
Under HMA, disabled access to all root apps (I have a big list)
Rebooted and then tested