It's nice to have you in the Community. Allow me to help share some information about matching and unmatching transactions from your bank feeds.
You can remove multiple deposits you've approved from the Transaction list window. Let me walk you through how to do it at one time in QuickBooks.
After that, you need to categorize the payee and account to save the changes. Once done, Quick Add the transaction to the register so that it won't go back to the Auto-Matched again.
The following article contains more information about this: Add and match Bank Feed transactions.
To answer your second question, generally, the downloaded transaction will be added to your register in QuickBooks. To better isolate your case, I recommend checking your bank register through the Chart of Accounts.
You can also use the Find command tool to see the transactions easily. Just click the Go to button at the top left, then enter the desired filters. Click Back or Next to locate them.
These resources should help to get you back on track to manage your downloaded transactions. Drop me a comment below if you have any additional questions about bank feeds. I'll be happy to help you further. Have a great day ahead.