You do not need to do all of this. Begin with the part that feels kindest.
Predictability feels safe
Rain is textured but steady. Unlike a notification or a passing conversation, it rarely asks the brain to interpret what comes next. That consistency can make a room feel less demanding.
A softer edge around the world
Continuous sound can reduce the contrast between silence and sudden noises. A closing door or a car outside may feel less noticeable when it rises from a bed of rainfall.
Build a simple ritual
Use the same gentle rain sound while you read, stretch, or prepare for bed. Over time, repetition can become a cue: the active part of the day is ending now.