Thank you for the detailed response. However, it doesn't seem to address the core issue. 

I have December 2023 sales and fees in Etsy that I'd like to bring into QB. I know how to sync the two to make that happen. Unfortunately, I used my personal bank account for these sales and fees in December 2023 so I'd have to use that personal bank account for both Etsy and QB, for December 2023.

For January 2024 forward, I have a new separate bank account I want to use for both Etsy and QB. How would I go about changing the default bank account for both Etsy & QB while synced? Or must I de-sync the two, change the default bank account on each separately, and then re-sync them?