No power unless I disconnect the keyboard and reconnect it

It’s likely a power delivery or keyboard flex cable fault in your Surface Laptop 5. When the ribbon cable is reseated, it temporarily restores the connection, allowing the laptop to power on. Try these steps: update firmware and drivers, perform a hard reset (hold Power + Volume Up for 15 seconds), and check for debris or damage on the ribbon and connector. If the issue persists, the keyboard-deck assembly or power button circuit likely needs replacement. Visit a Microsoft Authorized Service Center.