System lockups on 14-current with Plasma 5

I was just wondering if anyone else has experienced random freezes where
everything except the mouse cursor becomes completely unresponsive.

This began when I would come to my computer in the morning and find the
screen black and the system in sleep mode. It would not wake up to
keypresses or mouse movement. So I disabled power management in Plasma 5.
This still happened after disabling power management, so I disabled the
screensaver. That's when I would come to find my computer in the morning
with the screen still on, but as soon as I would click on anything,
everything but the cursor would freeze. At first, I thought it would happen
only after being idle a long time. But then it began to happen while
actively using the system after even a short time like less than an hour.
It progressively became more frequent over a few days until it would happen
immediately upon logging into Plasma 5.

I originally installed 14-current onto a spare laptop hard drive that I
installed on a secondary SATA port on my desktop just so I could test it.
But after these issues occurred, I suspected a faulty hard drive and
decided to install 14-current onto my main hard drive in a separate
partition alongside Windows 10 and Gentoo. I went ahead and disabled sleep
power management and the screensaver on the new installation. But I soon
began  to experience random lockups during use.

I installed Gnome 3, LXQT, and Cinnamon desktops to try as alternatives.
Maybe I haven't tested enough, but I have yet to experience any lockups
with these other desktop environments.

I had previously run Plasma 5 from quarterly on 13.2-release without any
lockups. So maybe it's an issue with Plasma 5 from the latest repo. It's
hard to know since there apparently is no quarterly repo available for
14-current. So it's unclear whether the issue is with the latest Plasma 5
or some compatibility issue with Plasma 5 on 14-current that I did not
experience on 13.2-release.