how to move an app shortcut from taskbar overflow to the taskbar

If you’re talking about the System Tray overflow, just click the arrow to open the overflow window and drag the shortcut to the System Tray.

I'm using the wrong term.  See  the arrowed items.

I'm referring to the three dots in between the taskbar at the bottom of my screen and the system tray.

What is the list revealed by clicking on the three dots called?

I want to select specific items to appear in the main task bar, without having to repeatedly remove items on the main task bar until the item I want finds room to appear on the main task bar.

Are you using something besides Stat11 to control or alter the taskbar? I don't recognize the three dot "More" menu.

not on that win 11 enterprise machine. When I hover over the three dots it says "Taskbar overflow menu"

Have you tried dragging the upper border of the taskbar up?

That's the normal Windows 11 taskbar.  When it runs out of space it puts the overflow on a ... Menu.  Unfortunately it also seriously miscalculates how much space it needs sometimes and forces things into the overflow when there was sufficient room.

If you enable the Start11 enhanced taskbar it will not do this.