Meditation app? I used to use one of those when my stress levels were very bad - and it really did help me sleep.

I used Insight Timer. It's got a good free version, and you can pay for more options. I actually spent a couple of years on the paid version - even though the free had all I needed - it had made such a difference to my sanity that it was my way of thanking them.

It's got a lot of tracks for sleep and stress.

https://insighttimer.com/