I don't recommend you to use it with non-Huawei devices. It will add all kinds of issues.
That makes it difficult to test and get the replies from and responses to .MakePurchase and .ObtainOwnedPurchases right before uploading the app to the Huawei store.
But its definately true, now I'm getting
"There was a problem while parsing the package"
when installing with the B4A bridge after adding the HMS Manifest lines and AdditionalJars to an app that was installing fine before I updated the phone with the HMS from the store.
Even though I have several other apps on the store, they are either free or paid so I can use the normal Andeoid apps straight up.
Wanted to do a couple of subscription apps though and without the HMS it's going to be difficult.