Context: Cmd-Tab in macOS switches between the foremost windows of open applications (i.e. never between windows of the same app).
I don’t have a solution for you, but if you used the complement feature cmd-` (switch between open windows of the currently focused app) I did implement that for Windows: https://neosmart.net/blog/2017/easy-window-switcher/
I don’t have a solution for you, but if you used the complement feature cmd-` (switch between open windows of the currently focused app) I did implement that for Windows: https://neosmart.net/blog/2017/easy-window-switcher/