Untested, but:
diff -Naur /usr/share/lipstick-jolla-home-qt5/volumecontrol/Screenshot.qml work/b/usr/share/lipstick-jolla-home-qt5/volumecontrol/Screenshot.qml
--- /usr/share/lipstick-jolla-home-qt5/volumecontrol/Screenshot.qml 2021-11-05 19:58:51.661137361 +0100
+++ /usr/share/lipstick-jolla-home-qt5/volumecontrol/Screenshot.qml 2021-11-05 20:14:40.496900431 +0100
@@ -40,7 +40,7 @@
//: Filename of a captured screenshot, e.g. "Screenshot_1"
//% "Screenshot_%1"
- var filename = fileUtils.uniqueFileName(folderPath, qsTrId("lipstick-jolla-home-la-screenshot") + ".png")
+ var filename = fileUtils.uniqueFileName(folderPath, "Screenshot_%1" + ".png")
var filePath = folderPath + filename
shareAction.resources = [ filePath ]
As I said, not sure if fileUtils.uniqueFileName will be able to pass the parameter this way.