need to restore all data in my previous iphone 6 from 4 months ago as it had software damaged & never backup before

I am going to try to understand what you are asking because I don’t think it is possible. You have an iPhone 6. You have not backed it up for 4 months. You have data that you want to access. This part is not clear to me. Do you want to get the data off the phone or put it back on the phone? Any how, somewhere in the past 4 months you had a software problem. Are you able to turn the phone on and use it? If you can’t use the phone and don’t have a backup of that phone, then you can’t do anything with the data. So, we need to know the current status of the phone and what you need to do.

You may restore a backup to your current device. Just be aware that the backup will replace everything that is on your phone now. So, depending on how old the backup is, you may not want to lose your current data.

moemen256 wrote:

& never backup before

Restore must start with a previous backup.

You have no previous backup. Therefore, restore is not possible.