Those instructions are pretty close, although you definitely don’t need to create the bind mounts and manually chroot like that. Here is the recommended way to do this maintenance:
I agree with @filo, after you set up the chroot you should reinstall Grub and bring your system fully up to date with garuda-update, then try booting normally again.
If you run into any issues, log into the forum from the live environment and paste the terminal output into the thread so we can take a look.