I mostly followed this guide here to have an chroot with internet access in recovery mode:
https://together.jolla.com/question/...#post-id-45710

You have to change the rootfs mount on Jolla C to /dev/mapper/sailfish-root.

After that you can use pkcon / zypper to fix your packages. Try to upgrade the packages and see, if you get errors with missing / wrong dependencies and try to fix them.