SHOPWARE_CDN_STRATEGY_DEFAULT seems to make no change

[teceP]

We want to use a S3 Bucket for our media and thumbnail directory.

I configured a rewrite (with Istio), so every Request to /media or /thumbnail will be proxied to our public S3 Bucket.

The problem is, that the file urls has not matching path to the actual S3 location.
Example, this is the rendered URL in the HTML: ..../thumbnail/0b/fe/e7/1695201649/9881885-1_1920x1920.jpg
But it should be a different timestamp.

I read that there is something like a "strategy" to prevent pictures get cached, so the timestamp will change from time to time (or on a specific action)?
Since we upload our files to the S3 Bucket, how can those picture paths get changed on time in the S3 Bucket?
If we use the filesystem configuration for shopware, all picture paths in the HTML will uncover our S3 Bucket URLs. It looks better if the pictures are also loaded with the same URL as our shop has. Thats the reason why we want use the rewrite-solution currently.

I searched for a solution and found the SHOPWARE_CDN_STRATEGY_DEFAULT env variable, but there is no change at all for the URL composition for our picture links.