If you got locked out and cannot access your DigitalOcean server but still have access to your DigitalOcean account, then here is a workaround to regain access to your server data.
Take a snapshot of your droplet from DigitalOcean
Create a droplet from the snapshot taken – right here you will be given the option to add an SSH key, add your new one or even choose password auth.
After the new droplet is created, you can SSH using your chosen key to the new droplet and access your old data.
You may delete the old droplet and update your DNS and apps to use the new IP address – or if you are using a floating IP then just let it point to the new droplet!