help for end user with deleted account and saved chat files

Hello, I'm an end user not a developer. But I have a difficult question with no answers on the internet, and no answers from LINE help. I backed up all my messages to Google Drive. I then changed phones and accidentally deleted my LINE account (I did this by deleting a second LINE account. I didn't know this would also delete my primary account). Now I have a new LINE account on my new phone, and all my original chats saved as files on Google Drive. But I have no way to view the original chats from my deleted account, or my contacts. Does anyone know how I can easily view these chat files that are on Google Drive? Or better, is there a way to import them into my new account? Or find my contact's IDs? Any help would be much appreciated.