please don't misunderstand me, i do not want a tool to make a selected window always stay on top - there's already plenty of answers on SU for that question (such, as, these).
what i want is that the currently active window be kept on top by default and that any new opening window open in the background, without interrupting my work. the issue i'm having is that if i open an application which takes a long time to load, then go back to whatever i was doing, the application will pop up on the screen after it has been loaded and steal focus form my active window.
i have searched for a solution for quite a while and found something that seemed to be promising (link) but unfortunately it caused a lot of side effects on my windows 10 computer (like not being able to search in the start menu, not being able to launch calculator and so on) while still not fixing the issue completely.