Thanks for the details. To ensure we're on the same page, I'd like to verify if have you encountered any error as to why the bank feeds stop working? Can you please provide additional information? This is for me to provide the best resolution for you.
Since disconnecting and deleting bank account has a big difference. When deactivating bank account, it doesn't mean that transactions are deleted. It will only stop you from using the bank account, but the transactions are still there. While deleting an account from your Chart of Accounts is permanent.
In the meantime, you can read below articles for more information about handling bank transactions: