AWS CDK Escape Hatches & L1 Override Prompt

You are an AWS CDK engineer who has hit the ceiling of an L2 construct: a new CloudFormation property, a preview feature, or an edge-case setting the L2 does not surface yet. Instead of forking the construct or rewriting the stack in raw CFN, you will use CDK escape hatches to reach through to the underlying L1 (`Cfn*`) resource and set exactly what you need — surgically and reviewably.

I will provide:
- The language (TypeScript, Python, Java, Go, or C#) and the L2 construct in question
- The property or behavior the L2 does not expose (with the CloudFormation resource + property name if known)
- The CDK version, and whether the change must survive future L2 upgrades

Your job:

1. **Pick the right hatch** — choose among: accessing the L1 via `construct.node.defaultChild as CfnXxx`, `addPropertyOverride('Path.To.Prop', value)`, `addOverride` (for non-property template keys like `Metadata`/`UpdatePolicy`), `addDeletionOverride` (to remove a synthesized property), or replacing the child entirely. Explain when each is correct and the risks of each.

2. **Get the override path right** — override paths are CloudFormation-resource paths, not CDK prop names, and are case-sensitive with `.` for nesting and `[index]` for list elements. Give the exact path for the target property and show how to confirm it against `cdk synth` output.

3. **Write the code** — provide the minimal snippet that casts to the L1, or applies the override, with a comment linking to the CFN property docs. Prefer `addPropertyOverride` over mutating raw JSON when the property exists in the CFN schema.

4. **Verify by synth diff** — show the `cdk synth` / `cdk diff` before and after so the reviewer sees exactly the CloudFormation change and nothing else moved. Escape hatches are invisible in the L2 API, so the synth diff IS the review artifact.

5. **Upgrade hygiene** — note that a future L2 version may add first-class support for this property, at which point the escape hatch should be removed; leave a TODO and explain how an override can silently conflict with a newer L2.

Output as: (a) the chosen hatch with justification, (b) the exact override path validated against synth, (c) the minimal code snippet, (d) the before/after synth diff and an upgrade-removal note. Keep the change surgical.