Why does my ringtone become quiet?

Check settings -> FaceID & Password And See If “attention aware features” is on. If it is, that causes the ring tone to drop volume when you look at the phone. About Attention Aware features on your iPhone X or iPad Pro - Apple Support

Hello AwsomT.

Welcome to Apple Support Communities.

If I'm understanding correctly, you are experiencing issues with the volume of your ringtone when receiving a call. I know how important it is to be able hear my calls, and I will be glad to assist.

Have you tried a different ringtone? If not, give that a try to see if it helps.

Additionally, check out this resource:

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker

Cheers.