If workspace management is an another term for managing desktop/spaces, then you are going to be hard pressed to find anything that is not a brittle hack.

I am writing a window manager bundled with other knick-knacks for myself. I have a "solution" for moving windows between spaces, but in the most vile way possible.

The only way I have managed to move windows between spaces is by, and this is no joke, recording the mouse position, moving the mouse to an app's titlebar, automating the 'click and hold' on the window's titlebar, then having the keybindings for "Switch to Next/Previous Space" fire off, and then moving the mouse back to the original position.

Because of the animations, all of junk requires carefully timed, short sleeps, which are also not likely consistent across various hardware/OS versions (can't test it myself).

Also, I have no idea what happens if my solution is tried on apps with pop-up windows, 'headless' apps (no title bar), electron apps, etc..

Apple's support for spaces is notoriously atrocious. There is no clean way to move windows from one space to another or to create/delete spaces. Though there was a built in way in OSX Snow Leopard, IIRC. Why it was removed? I have no idea.

Aerospace creates its own virtual desktops/spaces instead of trying to fight against the OS. I have never used Aerospace, so I cannot comment on its efficacy. But that is probably the cleanest solution we currently have available.