A.D. Amorosi Famous since the top of the 1990s for bold, old-school, synth-rich productions of hardcore rappers (Scarface), multi-hyphenate hip-hop magnates (Kanye West, Travis Scott) and symphonically scored R&B vocalists (Beyoncé, the Weeknd), Mike Dean always sounds as if he’s having the most fun on his chill solo excursions. Take the surprise drop this past weekend of “4:23,” another of Dean’s schmoked-up stoner efforts that, like 2020’s buoyant instrumental album “4:20,” is equal parts steely sci-fi epic soundtrack and spaced-out dream-pop.“4:23” is occasionally reminiscent of Dean’s home-recorded, souped-up synth-works, full of proggy impromptu noodling carved from larger ice block suites. But this new album mostly features tracks more succinct and cutting — actual songs. For such freshly anointed precision, we can likely credit Dean’s steadfast collaborator, tour partner and streaming network co-star, the Weeknd, who takes on a role here as the executive producer of “4:23.”