How to backup my iPhone without access to Internet, PC or a Mac?

I have unlimited data available on my phone, but my plan does not let me create a mobile hotspot. So I can’t even share my own data. I am also in a place where I do not have access to Internet or a computer and my iPhone needs to be backed up.

Is there any way I could possibly get this done?

You can enable iCloud backup in your settings. You will not need to create a hotspot, only use your data to upload the backup to your iCloud account.

A mobile hotspot would not help in this scenario - that is to enable other devices to connect to the internet through your iPhone - but requires, of course, that your phone can already connect to the internet. It would not help your connect you phone to the internet; for that you would need a net-connected computer or WifI.

If you have no internet connection & no computer, you cannot make a backup.