Our USD account is based in the United States, so it does not use a Canadian transit or institution number. If Stripe is requesting these details, it likely assumes your account is based in Canada and this needs to be switched to the United States.
Step 1: Go to "Stripe external payout accounts and scheduling"
Step 2: Edit the account associated to the receipt of USD
Step 3: Under the "Country of bank account", select "United States"