Is there a way to auto spectacle every app / window that I open from different programs upon opening?

I set my windows to what size I like. Here is how I use my web browser.

You can adjust the windows to what size you like. The come back to that size the next time you start.

For some reason, Windows seems to want you to work on one app at a time in full screen. In the mac, I have multiple apps open at once.

One of the great features of macOS for me, is to use a keyboard manager, keyboard maestro. I have set up F2 to be mail, f5 to be edit html, f4 to be a web browser, f8 to be bbedit and shift f12 to be activity monitor. The neat thing is you can press these key to start the app or switch to the app. Thus, there is no worry about whether the app is running or not. Thus, when I press f4, I get my web browser. I can "play" my function keys to quickly move between applications.