No Sound from Marantz Cinema 50 When Playing from MacBook Pro

I recently bought a Marantz Cinema 50, but I can’t get sound through its speakers when playing video or music from my MacBook Pro (M1 Pro, Sequoia 15.3.2). Would appreciate any help troubleshooting! Setup - AVR: Marantz Cinema 50 - MacBook: M1 Pro, Sequoia 15.3.2 - Projector: Epson (likely not relevant) Connections - MacBook → (HDMI 2.0) → AVR (HDMI IN 1 or 4) → Expect video on projector & audio via AVR speakers. - AVR → (HDMI OUT Monitor 1 ARC/eARC) → Projector. MacBook Settings - Sound Output: Set to "Marantz 50 (HDMI)" (not AirPlay). AirPlay works fine. - Audio MIDI Setup: 2ch 16-bit 44.1 kHz (tried different settings, no change). Primary Stream is greyed out (Mac doesn’t seem to detect a speaker). Marantz Settings - Input: Set to HDMI (fixed for HDMI 4). - ARC: OFF. - HDMI Audio Out: Set to AVR (not TV). Results - Video works fine on the projector. - Audio issues: - Spotify: Lags & repeats short loops before continuing. - GoPro videos (VLC): Sound is laggy. - YouTube/Netflix: Video doesn’t start unless I switch sound to MacBook speakers. What I’ve Tried - Multiple HDMI cables. - USB-C to HDMI adapter (Apple official). - Tested all HDMI IN ports on AVR. - Reset both devices multiple times. I’m new to home theater setups, so any guidance would be much appreciated. Thanks in advance!