Managed pricing single plan

On my app I want to use managed pricing with a single plan required for every customer. On install the customer should be redirected directly into payment for that single plan without going through shopifys plan section page (because only on plan).
There is no option to require subscription to a plan in the apps shopify.yaml. Also I can not generate a payment url for managed pricing via appSubscriptionCreate in the admin api for managed pricing plans.

Is that correct or do I miss something?

With managed pricing you can’t automatically direct to the payment page at the moment. The merchant has to select a plan.
It also gives you a chance to sell your apps features and educate the merchant on the value of subscribing rather than a surprise payment page.