Hi there!
You will need to restore data manually, I'm afraid. The easiest way to copy all your files over is using a USB drive. You can copy all documents, photos, etc. this way.
Some apps have their own internal backup mechanism, like Signal, Aegis, Tasks.org, etc. You can backup those on your 4a, and then copy across the backup files to your 7 Pro the same way.
You can backup your Contacts to a .VCF file with the default Phone app. If you want to restore SMS messages and call logs also, you can use an app like: https://github.com/tmo1/sms-ie
You can restore WhatsApp data using a Google Drive backup, or manually, by copying the Android/media/com.whatsapp directory from your 4a to 7 Pro.
If you have any further questions, please don't hesitate to ask.