Reading other thread about the hard aspect of newbs understanding item control, it could be addded a modifier in custom unranked games/practice games/even a ???new-standard-mode-for-practice??? and wherever else it could help... this:

Items always visible, yep thruwall too like the yellow triangles of teammates, and when you pick them the item its replaced by a counter that displays the time left for it to appear again, which you also can see from any part of the map. When the time is up, the counter is replaced by the spawning item.