Hi

The classic quiz engine (legacy) and new quizzes LTI are not connected.

In Legacy / Classic Quizzes

The fastest way to move the question banks from the legacy system is to create a classic quiz, pulling questions from a bank using the find questions. Name the quiz exactly as you want your item bank in new quizzes named.

In Settings

Next, export the classic quiz using settings >> export >> quiz. Save the file.

In New Quizzes

Go to the new quizzes LTI Item banks, enter the item bank list (3 vertical dots - "Manage Item Banks") and choose the item bank you created or create a new one. Choose import from the 3 vertical dots. 

We’ve moved hundreds of banks this way. You should do one question bank at a time. 

Good luck!