Hello, Larna Hadfield.
Welcome to Microsoft Community!
To help you regain access to your Surface Laptop 5, I am going to share with you a complete process of resetting the device with the help of a USB recovery drive.
We need to use another computer to access the following site to get a dedicated image file for the Surface to create the recovery drive:
Surface Recovery Image Download - Microsoft Support
Get it by logging into your account and entering your device's serial number:
After completing the creation of the recovery drive, continue to refer to the guidelines in the following link to complete the recovery operation:
Creating and using a USB recovery drive for Surface - Microsoft Support
The link shows us a complete demo video and key textual guidelines:
If you were able to complete the reset of your Surface Laptop 5 by following the steps above, you can mark my reply as an answer by clicking “Yes” or “No” below the reply. This will enable more users to understand the steps to complete the reset installation for the convenience of the users in community.
Of course, if you have any doubts about the process, please don't hesitate to let me know. I am here to support you.
I wish you all the best.
Best Regards.
Leo.L - Microsoft Community Support Specialist