Ever since the KDE Frameworks 5.70 update, I've had an issue where dragging most desktop icons to a new position crashes Plasma. It only happens with those that are the actual icon and not a thumbnail of the content as the icon. I saw that there is a bug filed on it, though I do not have the number handy.

If anyone else runs into this, I've found a workaround. Simply use the command line or package manager of your choice to revert plasma-frameworks to version 5.69. After that, a restart of plasma (or you could just reboot) should fix it. Be sure to lock the package so it's not updated once again to the faulty version.

I had this issue on all of my PCs running Neon, so I am surprised that there is no post about it here (if there is, I missed it in my search). If anyone has a better workaround or a fix for the issue that doesn't involve reverting the package, I'd be interested in hearing it. It is possible that the changes that broke plasma-frameworks were made in preparation for a future version of some other package, so the problem may resolve that way in time. For now, this workaround can make things work as expected on the desktop once more.

I have exactly the same problem, both in my home on my PC, and at work in a VirtualBox on a Mac...

Same here, desktop crashes when i drag drop an icon in the desktop. Taskbar disappears and background image turns into black. Alt-tab and already opened windows works fine.
It recovers first crash and reloads taskbar but it does not recover second time. I have to crtl + alt +delete and logout then relogin.

The last update this weekend solved the problem. Big thanks for the KDE team!