3d item drops are very laggy on mobile devices. On a medium phone it drops to 20 fps when there's 7 stacks of items on the ground. Which is strange because the blocks as items are also 3d but they aren't laggy at all (unless you break a full double chest but that is expected)

In the 2 screenshots you can see that the 3d items (7stacks)

Put the fps down to 20 but the block drops which are 3d as well (7 stacks) is totally fine: fps 53