If you didn't back up to Samsung Cloud or other places like Google or Dropbox as some examples then theres a good chance the deleted items are lost.
Now there are software programmes available to purchase that purport to be able to recover deleted files but as I've not used them I can't recommend one.
I'd suggest to perform some Google searches and look at reviews to see how effective they are.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.
Actually, Android data recovery software can help us recover deleted message and photos on your Samsung J7 before they are overwritten by new data. You just need to connect it to computer, start the software.
Samsung Data Recovery can be a good helper here. It is a professional software designed to restore the Samsung data that are wrongly deleted or accidentally damaged. It can help you to retrieve the files on Samsung device like contacts, text messages, call histories, music, photos, videos, audios or other data without any hassle.
To recover contacts, messages or call logs from Samsung J7 with this software, there are two things you need to do beforehand: enabling the USB debugging and rooting the phone.
First, check out Samsung Cloud or Gmail or Dropbox. If you don't turn off automatic syncing, it may be automatically synced to the cloud server so you can retrieve them. If it is not found, then scanning the phone to recover Samsung J7 deleted messages is the last choice.