Many Thanks to each of you for sharing your knowledge. It's always a good day when I get to learn something new.
From reading each of your replies, it seems the safest & ultimately the most convenient plan is to keep the SD as Portable Storage, using it for documents, photos, music and such. Some of the apps let larger, static components go to SD, such as maps, while the application stays on the phone. That's helpful for saving storage.
As Hadron mentioned, internal storage is 128 GB on Moto G Stylus. On the old phone, any apps that allowed it went to SD to keep them isolated from the phone in case they went haywire. But, after reading what Hadron said about only part of the app moving to SD it appears my genius idea was not so genius at all.
Thanks Again All for helping & for the great explanations.
Please Enjoy Today!
Paul