how do I move data from my MacBook Air to my iMac? without migration assistant and above mentioned as it was not helpful

The best option if not using MA will be an external SSD connected to the old Mac, your user files and folders dragged and copied to that, then transported to the new iMac and copied onto that.

This will require that your new Mac already be properly set up and is simply taking your user files to it, ignoring network settings and all misc OS info.