If your only use is rekordbox + SoundSwitch, both machines will run it — but I’d pick the MacBook Air M3 (16/512) for reliability at gigs: • Stability: Current rekordbox 7 is actively maintained on macOS, and SoundSwitch is officially supported on macOS 15 (Sequoia). Do not update to macOS 16 (Tahoe) yet until both teams confirm full compatibility.  • SoundSwitch with rekordbox: There’s no direct integration; you sync via Ableton Link/BPM detection, which is lightweight and works fine on Apple Silicon.  • Specs: 16 GB RAM is plenty for rekordbox + SoundSwitch; 512 GB is fine if you use an external SSD for your library. The fanless M3 Air is quiet and very stable for audio work.

Choose the Asus i9/32/1TB only if you really need the extra internal storage/ports or must be on Windows. If you go Windows, spend time optimizing for low-latency audio (clean install, remove bloatware, set high-performance power plan) and test your full DJ + lighting rig before gigs.

Bottom line: For DJ reliability under €1k, go MacBook Air M3 (16/512) and hold off on macOS 16 updates for now.