In Windows, it saves the last state, so mine generally open in 'Maximized', but it's also quick to do. macOS never opens in maximized so they always float somewhere, and you only have the option to go Full Screen, which is different as it puts it in its own desktop space.
Actually, macOS will remember the last state too. Try it. Open Music. Hold the Option key and left-click the green bubble at the top left of the window to maximize the window. Quit Music. Open Music again. It opens maximized. Same thing happens with Mail, Messages, Maps, etc. Microsoft Office for Mac also remembers the state of the window size on a per-file basis.
I do wish macOS had native support for window snapping like you mention, but it's definitely not a deal-breaker for me and I don't use any third-party apps to do it. I simply manually resize as need, and--as I said--they open to the same size and position next time I open the app (which Windows doesn't do, so you could actually argue macOS is better in this respect, because once you position the window where you want it, it will open just like that the next time and you don't have to resize or "snap" it back again).