“My head is a box filled with nothing,” sang Ben Lee on his ARIA-winning 2005 single, “Catch My Disease.” But looking at the Australian songwriter’s bountiful, sidewinding career, it’s obvious that his head is overflowing with ideas. How else to explain his ever-changing selection of collaborations, concept projects, and multimedia pursuits? After getting his start as a mid-’90s teenager in Sydney indie rockers Noise Addict, Lee broke through as a solo artist with 1999’s “Cigarettes Will Kill You,” a wounded breakup song that rolls along with plinking piano, looped beats, and unabashed lyrical revelations. He has retained that earnestness alongside generous dollops of dry wit, channeling classic power-pop anthems on 2007’s “Love Me Like the World Is Ending,” brandishing a ukulele for 2015’s bubblegum valentine “Big Love,” and duetting with Megan Washington on 2022’s cheeky “Parents Get High.” No matter who he’s working with or what mode he’s in, Lee performs straight from the heart and never seems to care how uncool that might make him look.