EC2 "Instance reachability check failed" network adapter disabled

Hello.

You may find the troubleshooting information in the following documents helpful.
I think you will be able to connect by creating a new ENI and replacing it.
https://repost.aws/knowledge-center/restore-network-connectivity-windows

The below blog can address your issue https://aws.amazon.com/blogs/compute/using-the-ec2-serial-console-to-access-the-microsoft-server-boot-manager-to-fix-and-debug-boot-failures/#:~:text=EC2%20Serial%20Console%20provides%20a,key%20locally%20on%20your%20client.

You cna access the instance using EC2 Serial Console. EC2 Serial Console provides a Secure Shell (SSH) to securely access SAC via your Windows EC2 instance’s virtual serial port. Connection to the virtual serial port does not require instance network connectivity. Therefore, you can use EC2 Serial Console to fix the networking misconfiguration.