TBYB Selling Plans for subscriptions

Shopify Apps
1

Is there a way to create a SellingPlan that mimics TBYB, but for subscriptions? I guess it would be TBYS (Try Before You Subscribe)?

Basically, what I want to do is add a product to the cart, associated with a subscription selling plan, which should have no charge during checkout, but all subsequent charges should happen normally.

Here’s the selling plan group I’m using

{
  "appId": null,
  "createdAt": "2025-03-13T23:51:23Z",
  "description": "All available frequencies for Subscriptions",
  "id": "gid://shopify/SellingPlanGroup/23423412341",
  "merchantCode": "Subscription Cadences",
  "name": "Subscription",
  "options": ["Delivery every"],
  "summary": "8 delivery frequencies",
  "productVariantsCount": { "count": 1 },
  "productVariants": {
    "nodes": [
      {
        "id": "gid://shopify/ProductVariant/7298374928374",
        "sku": "MYPRODUCT"
      }
    ]
  },
  "sellingPlans": {
    "nodes": [
      
      ...,
      
      {
        "id": "gid://shopify/SellingPlan/29374982734",
        "name": "3-Week Cadence",
        "options": ["3 Week(s)"],
        "position": null,
        "category": "SUBSCRIPTION",
        "pricingPolicies": [],
        "billingPolicy": {
          "createdAt": "2025-03-13T23:51:23Z",
          "interval": "WEEK",
          "intervalCount": 3,
          "maxCycles": null,
          "minCycles": null,
          "anchors": []
        },
        "deliveryPolicy": {
          "anchors": [],
          "createdAt": "2025-03-13T23:51:23Z",
          "cutoff": null,
          "intent": "FULFILLMENT_BEGIN",
          "interval": "WEEK",
          "intervalCount": 3,
          "preAnchorBehavior": "ASAP"
        },
        "inventoryPolicy": null
      },
      
      ...

    ]
  }
}

Is it possible to achieve this “TBYS” plan? If not, is there a way to use normal TBYB and later convert that mandate to a subscription contract?

Thanks in advance!