Thank you for the detailed comparison. I found a log upload under your name from 15.0.1, but it starts with playback already running and doesn’t identify the LDAC setting or the exact stutter times.
Please update to production 15.1.0 and try again. Read the release notes and APK instructions; if Google Play has not approved that release yet, the announcement explains how to get the official APK.
If it persists, please capture fresh debug logs. Enable debug mode before starting a track at 990 kbps, reproduce the stutter with Symfonium visible, switch to another app, then return to Symfonium. A brief comparison at 660 kbps would also help. Disable debug mode and upload promptly.
Reply with your app version, Bluetooth device model, upload description, and the times when stuttering starts and stops, including your timezone, so I can correlate them with the logs.
Also try to capture a full bug report https://developer.android.com/studio/debug/bug-report after it stutter then upload it to https://upload.symfonium.app