@jdechong Thank you for that information! That actually clears up what I was thinking was going on. From the way that you described the conern, it seemed like the phone was killing your background apps, which can eliminate notifications from coming through until your phone is open. Most phones will allow apps to run in the background, but this can kill the battery.
After doing some research online, I found that the Huawei model phones were developed to help make your battery last - but at a cost. The technology on the phone, especially when the phone has Harmony OS (most Huawei phones have this), is designed to actively kill your background apps from running in the background. It seems many people with the Huawei phone have had issues with notifications coming through, not only for the Ring app. Forbes even made an article on troubleshooting for this phone!
Since the phone has this intense level of battery management, the phone will cause apps not to deliver notifications when they are running in the background and there seem to be a few articles on the web that I have found that support this. My apologizes that I am unable to help further, but I recommend checking out that Forbes article and maybe reaching out to your phone’s provider specifically for more advanced help on this concern. 