I am having this same issue with Bank of America (BOA).

Last week I set up a new company in QBO using the balance sheet entries from when our previous accounting firm kept the company accounting under their QB account.  The new company only has two banking accounts (checking & CC that are both through BOA) and there were only 7 total accounts to enter opening balances for - it should be a VERY SIMPLE company to manage in QBO.

The bank accounts sync to show the correct balances for any given time period between now and the opening balance date (9/1/2020), however, only one (1) transaction is showing up for the checking account and one (1) transaction shows up for the CC.  I have checked my login information, permissions, and settings numerous times - and I know that they're correct due to the balances for any given time period showing up properly.  Since BOA is one of the largest banking institutions, I doubt that this issue is due to an inability for connection between QBO and BOA.

When I switch to another QBO company of mine, there's no issue syncing and viewing bank transactions from other smaller credit unions and credit card companies.

So, what do I do from here?