Can you check your Google play device certificate ?
I believe it's "uncertificated".
This will block Google Pay safety verification, you should see some message like "your device is rooted or altered".
If this is what you saw on your device, all you need to do maybe is to just wait. This issue happens on newly released Huawei devices. Last year I bought P20pro and got this problem until around 4th or 5th month after release, now it works perfectly.
For the recent Google ban, I don't think Google would ban those released devices already in market. Usually when a device is "uncertificated", all google play, mail, map service won't work at all. What we saw on P30pro is that Google Play is working and allows purchasing new apps without problem. This means p30pro is supported by google play as a registered model. The chaos comes from the upgrades between google play and google pay, they are not updated in the same time and for new entry devices google pay only works when google play fully updated with latest certificate list.
It could be hard or impossible for later Huawei products like Mate30 to get GMS or let legacy Huawei devices get Android Q update. When google fully move to Android Q, Android 9 based device could be dropped from the support list, but that happens only after 2 or 3 years from now. Even without ban, we would switch to another phone by then.
Even google pay is disabled, NETSPAY is still fully functional on my P30pro. As long as we use NFC pays in Singapore only, Google Pay is replaceable until we switch device in next contract cycle.