I agree with Brandon, austinoccasions. 


Backing up is always the best practice to safeguard your company file. 


You can request from your bank a .qbo file format for your transactions. Then manually upload these to QuickBooks. 


You might want to use the QuickBooks Mac 2019 trial to migrate your data in QuickBooks Online. I have prepared articles that can help you along the process. 

Mention me if you need anything else.