5 Seconds of Summer bassist Calum Hood steps into the spotlight alone on his solo debut “Don’t Forget You Love Me,” an enthralling introduction that finds him walking a tightrope between self-reflective (and at times self-destructive) despair and relieving reconciliation. The record will appear on his debut album Order Chaos Order, out June 13, which emerged from a kindred dichotomy.

“This album was made in a tumble dryer of knowing and not knowing. I started out with a vision — order — but quickly became overwhelmed by the process — chaos. Eventually, I learned to embrace both,...