Do authorization holds affect my account balance?

Yes. It can affect your available balance by lowering the amount you have to spend, but only temporarily.

Some businesses will place a hold when you pay, as part of their authorization process, and it’s usually more than the final charge. You’ll see that amount set aside in your account. Once the transaction settles, it updates to the actual amount.

In short, the merchant (not Novo) decides how long the hold stays on your account. But it's not permanent.