iPhone alarm volume lowers with system volume

How to fix alarm volume turning itself down when I lower system volume?

At night, I turn on the Background Sounds feature to listen to white noise. I lower my system volume pretty low to keep it quiet. Sometimes this will also lower my alarm/ringtone volume, so I won’t hear my alarm go off in the morning. This has happened multiple times for no reason. I have “Change with buttons” toggled off in Ringtone & Alerts settings.

iPhone 17 Pro, iOS 26.2.1

I used to have an iPhone 12 and it didn’t have this problem.