I've tried to apply any API switches to turn off caching that I've found.
Yes, given the way we're using the browser, it would be nice if it didn't do any caching at all, since there's no "bandwidth" to worry about.
Alternatively, is there a way to refresh the cache on demand?
I soon plan to switch from Java 19 to Java 20. In the v20 release, they have updated the underlying binaries for the WebView/WebEngine components. Hopefully this will improve several aspects of the embedded browser. Unfortunately, the updated JavaFX files requires at least Java 17 to run, meaning that we can no longer provide a Java14 version of jAlbum for users running older Macs.
The hardware lasts too long. If Catalina and earlier won't handle Java 20, that effectively cuts out any hardware that's more than about 10 years old. My 10-year-old Macbook Air is still perfectly healthy - even the "battery health" is fine. The processor is slow, compared to newer equipment, but the laptop isn't ready for the trash bin. It's running Big Sur, so it's still taking the latest Java releases without complaint.