No, there’s no simple connection between your WordPress and FTP access and access to your hosting, whether you mean either shell access to the EC2 instance or access to the AWS dashboard.
- Even if your FTP account is a real Linux user account, EC2 instances won’t accept password SSH logins by default.
- You do have permission to upload arbitrary plugins, meaning you can run any PHP code as the web server user, which is a theoretical route to getting access assuming there are unpatched Linux vulnerabilities on the box. But please don’t go down this route.
Your best bet is to talk to your technician again about setting you up with the right access: check he’s OK with you having access and not ignoring you because he doesn’t want to grant it; ask if he’s got anywhere figuring out what has gone wrong, check the username you need to use on the new host, suggest he sets up a new temporary key pair for you that definitely works and send you the private key, etc. If he’s not responding to emails try giving him a call instead.