Hi, let me help you.
Please try to open Task Manager while it's glitching and see if memory, disk, or one process keeps climbing. Then turn off hardware acceleration in your browser settings. In Chrome or Edge, open Settings, search "hardware acceleration," switch off "Use graphics acceleration when available" (or "Use hardware acceleration when available" in Chrome), then restart the browser. Test in a private window to rule out extensions. If it's still choppy, go to Settings > System > Sound, pick your output device, set the format to 16-bit 48000 Hz, and turn off audio enhancements. Setting your power mode to Best performance can help too.
If restarting the Windows Audio service (services.msc) fixes it for a while, it's most likely a driver, so check Device Manager for updates. Does it happen outside YouTube too?