From the original bug report:

Sometimes can't COMMAND+Click Qt Quick Controls to open their style-specific implementation QML files from the Qt install folder. Seen notably with ApplicationWindow at the root of a document.
It has been found that COMMAND+double-clicking can sometimes (but not always) open ApplicationWindow. However when it does work, it opens the wrong one - e.g. opening with Kit=6.7.2 opens the one from Qt 6.8 instead which is incorrect.
If the "Use qmlls from latest Qt" is unchecked, the double-click doesn't work at all.

From what I have seen, go to definition is not implemented in qmlls for ApplicationWindow, at least I could not get it to do anything for me. The codemodel from creator does currently support it.