How do I prevent code being read from the SAMD21 M0 Xiao?

Hi everyone,

I have been looking all over for a solution to this online but it is confusing me. The following two links both suggest they should enable the read protect fuses on the SAMD21 but when I have tried it on my xiao, I can still press the boot pin twice and copy the uf2 file from the xiao onto my hard drive.

What is the correct way to set the security bits so that the code cannot be read? I am happy to use another bootloader if needed

Thanks in advance