Perhaps the issue lies in the error message?
Code:
debug1: Next authentication method: publickey
debug1: Offering public key: /home/will/.ssh/id_kindle RSA SHA256:3OMCm0BM9fVLwqL141DjgXaibahnP36aVfDMUQZkj88 explicit agent
debug1: send_pubkey_test: no mutual signature algorithm
Not sure if you can regenerate the keys but that might be worth a try.