Is it possible to go back further than 2018 when lin king accounts
Yes, this is possible, karatusia.
When you first connect your bank account, QuickBooks Online can only download 90 days worth of transactions. Some banks allow up to two years just like your bank. To bring older transaction to QuickBooks Online, we can import a valid CSV file that contains your 2016-2017 bank transactions. We can request this file from your bank.
Once you've acquired the file, we can already import it to QuickBooks Online. You can use these links for reference on how you can import the file: