it is unintuitive but auto renew is independent of the billing "subscription" which you manage via Account Settings > Renewals & Billing > Manage Subscriptions. From there you can "Bulk Edit" and filter by "Auto-renew off" to then cancel the subscription on all your auto renew off domains. You'll still get some emails about expiry but not as many. The voicemails from my account manager are more annoying than the emails.
My recommendation is to create a separate GoDaddy account just for the domains you intend to let expire. You can then keep paying attention to billing failure notifications on your main account (which is where your good domains stay) but disable all on your expiring domains account.