Hi SS_80,
Thank you for reaching Microsoft Community. I'm sorry to hear about what happened to your Surface Book 3 keyboard.
The Surface Book 3 keyboard and clipboard are uniquely and securely bound or programmed with each other at the factory and are sold as a matched set. Because of the secure binding or programming, we could not just provide a replacement keyboard that would work with clipboard you have. We do not recommend also using a keyboard from another Surface Book 3 unit especially other Surface Book versions.
Liquid damage also is not covered by the Standard Manufacturer's Warranty. Please contact our live support team for options and further assistance. You may contact them through the numbers listed in Global Customer Service phone numbers (microsoft.com) under For Business users. This works with Home users also, just select Surface then Home as a type of user in the IVR prompt. You may also reach them through this page: Contact Us - Microsoft Support and use the details or entries given here: I need to talk to tech support - Microsoft Community. Please note: For USA region, they are available from 6:00AM to 10:00PM Pacific Standard Time.