KDE window rules can do this natively

Hyprland window rules can also do this natively

Gnome can also do this with extensions as mentioned

TDE has this natively under the advanced window settings, so I would expect KDE to have it too.

I do this with awesomewm. You define window startup behavior in the main config. Applications can have static behavior to start in certain places or will default to "wherever my cursor currently is". I suspect i3 has similar functionality

Herbstluftwm. It's one of the main reasons I use it.

You can run commands on the command line to create your layouts for one or more desktop (tagged spaces), assign programs to appear on tagged spaces, and then run the programs. Put it all in a shell script and hlwm runs it when it starts.

I use xtoolwait for programs I want multiple windows on different desktops for, like terminals.

I have three monitors; one is a status window, and the other two are grouped together in 8 different tags. Mod4+9 focuses the status screen, Mod4+[1-8] switch the other two monitors in sync to the other workspaces. It's all set up when I log in, including the creation of several terminals each running tmux from sessions restored by trum-session. The only thing I have to do is enter a password to unlock my secrets so background processes can start doing their thing.

Used to use fluxbox and it did this; fantastic feature.

Inst this simply KDEs activities?

This can easily be achieved in Gnome with a couple of extensions