You want to switch to an already running app? Alt tab or win tab doesnt do that?
The problem with *-tab is that each application has no fixed place in that space. So on every invocation I have to look, find, switch.
Contrast with bringing up Mail using Alfred. The behaviour is always the same, and therefore muscle-memory-learnable: Cmd+space, ma, return. Messages: Cmd+space, me, return. Near-instant for me because I've done it literally thousands of times.
BTW Win+1 to Win+9 will switch to the first 9 pinned items in taskbar. If there isn’t an available window it will open one. I have Outlook pinned as the 4th item on my taskbar so navigating to it is always Win+4.