Can my account is linked to my bank for 2020, if I only have 2021 linked?

Hey there, @david-sprintphyt.

You can follow the suggested steps that were by Fiat Lux - Asia in this thread. This way, you can upload your bank data from 2020. 

Here are the detailed steps on how manually upload files in QuickBooks Online (QBO):

1. In QuickBooks Online, go to the Banking menu or Transactions menu and select the Banking tab.
2. Click the blue tile for the account you want to upload the transactions into.
3. Select the Link account ▼ drop-down list and choose Upload from file.
4. Click Browse and select the file you downloaded from your bank. Then, click Next.
5. In the QuickBooks account ▼ drop-down menu, select the account you want to upload the transactions into. Then, click Next.
6. Follow the onscreen steps to match the columns on the file with the correct fields in QuickBooks and select Next.
7. Choose the transactions you would like to import and click Next.
8. Select Yes.
9. When you're ready, click Let's go.

In case you see any error messages, don't worry. Here's how to fix errors while uploading your transactions.

Once your transactions are in QuickBooks, it's time to match and categorize them. The transactions go into your accounts after you review them.

I'm always here to help if you have any other concerns or questions. Just tag my name in the comment section and I'll get back to you as soon as I can. Have a great weekend.