Seeking Guidance on Enabling Telnet Access via SSH Proxy Using F5 BIG-IP LTM

dabance I would not use your LTM as a SSH proxy, especially because the F5 will receive the traffic as SSH traffic and will not be able to switch to the telnet protocol instead. You're better off configuring a jumphost for everyone to use, installing telnet on that jumphost, and finally restricting management access to that jumphost IP. Having the SSH jumphost also allows you to track what each user does.