Unable to make NFC payments unless banking app is open

I bank with Barclays, who do not support Google Pay.

With my Samsung Galaxy S8+, I was able to make NFC payments, even when the phone was locked.

However, since I bought my Huawei P30 Pro back in March 2019, I need to have the Barclays app open and logged into it before I am able to make payments.

This makes it slow to make payments, so I tend to just get my card out. It's faster. Though it defeats the point.

I have disabled any battery-saving features related to the app.

Any ideas?