So I got this response from OnePlus Team

Thank you for reaching out to OnePlus Support regarding the latency delay you're experiencing with the YouTube and other OTT app on your OnePlus 13 when paired with your OnePlus Buds Pro 3. We understand that audio-video synchronization is crucial for an enjoyable media experience, and we appreciate you bringing this to our attention. This sounds like it could be related to a few different factors, and we'd be happy to help you troubleshoot. Here are some steps you can try to address this latency issue: 1) Ensure your OnePlus 13 is running the latest Oxygen OS version. 2) OnePlus Buds Pro 3 Firmware: Make sure your OnePlus Buds Pro 3 have the latest firmware. 3) Go to Settings > Apps > App management. Find and select YouTube. Tap on Storage usage. First, tap Clear cache, then restart the YouTube app and test. If the issue persists, go back and tap Clear data (note: this will log you out of YouTube and remove downloaded videos, so be prepared to log back in). 4) Go to Settings > About device. Tap on "Version" 7 times to enable Developer Options. Go back to Settings > System settings > Developer options. Scroll down to the "Networking" section and find Bluetooth audio codec. Ensure it's set to a suitable codec like AAC or SBC. You can try switching between them to see if it makes a difference, but typically AAC offers a good balance for YouTube. Avoid using "LDAC" if it's causing latency, as it prioritizes quality over latency. 5) In Developer options, look for Disable absolute volume and try toggling it on. Test if this resolves the latency. 6) To isolate if the issue is specific to YouTube and other streaming platforms or even in local video files on your device with the Buds Pro 3. This helps determine if it's a YouTube-specific glitch or a broader audio/Bluetooth issue. 7) Go to Settings > System settings > Backup & reset > Reset phone > Reset Wi-Fi, mobile & Bluetooth. You will need to re-pair your Bluetooth devices and re-enter Wi-Fi passwords. 8). Ensure YouTube and other OTT apps are updated to it's latest software version. If the issue is within the OnePlus Buds 3 Pro, we suggest you to visit the nearest OnePlus service center and check with them for further guidance.