I can no longer silence ringer on my phone

This week, my phone (iPhone XR) has stopped allowing me to put the volume down to silent. I've tried all the various tips for getting it to work (reboot, using accessibility settings to ensure that it's not just a broken button, Siri).

My question is this... is this a bug or a feature of the latest OS? Is there anyway to actually set my phone to silent without faking it with a silent ringtone and disabling other sounds? (There are times I want the volume on and don't want to have to go through reassigning ringtones and changing settings each time).