Thanks for the update, Mel.
Let me chime in on this conversation and add details to your follow-up questions.
QuickBooks Online (QBO) depends on the number of login attempts allowed by your bank. Signing in to your bank account through QBO, regardless of the browser, would count as an attempt because the same credentials are used. However, this may still depend on your bank since it is also possible that they allow logging in multiple times using the same credentials through software like QuickBooks. I recommend reaching to your financial institution to confirm this.
Yes, QBO would allow multiple times sign-ins until you input the correct username and password, but then again, this will depend on the login attempt policies set. After updating your linked bank account with incorrect credentials thrice, you'll receive an error like in the image below and an email notification about your bank connection not working. Still, you can redo updating your bank login info.

About your last follow-up question, my colleagues and I utilize providing articles as future help. We envision providing a holistic response to customer's concerns and anticipate future needs.
As a future help, I'm adding this article that guides what to do if you experience any issues connecting to your bank in QBO: What to do if you get a bank error or can't download transactions in QuickBooks Online.
You're always welcome in the QuickBooks Community should you have further questions about bank login attempts in QBO. Take care.