Here's a simple, powerful song that I sing to find comfort on hard days. Peace Like a River is a sweet song with very simple lyrics that make it easy to improvise your own verses. It uses the 1, 4, and 5 chords, and in the video I play it in the key of C (with a little "help" from my daughter).
Download a free PDF of the chord sheet so you can play along at home! Want to strum along to another version? Search Apple Music or Spotify (or wherever you stream your music) for Elizabeth Mitchell's version, which is also in the key of C. Happy strumming!