To check if your payment settings are activated correctly, log into the Stripe Dashboard and go the Settings > Payment Methods. If your desired payment options are properly enabled, you will see the "Live" badge next to them.
If they aren't activated, click the "Activate" button to enable the payment option or apply for activation. WeChat Pay has an application that you need to fill out to activate, and Alipay has a separate process. Both activation flows are subject to change by Stripe.
Alipay must be activated separately and supports one-time payments out of the box.
To enable Alipay subscription payments, you must make the request to Stripe support directly based on this article in their documentation.
After a discussion with Stripe support as of Dec 2020, they stated they plan to add a button in the dashboard and/or automate the ability to activate Alipay subscriptions on your Stripe account in the future.