Fedora login freezes

With F39 I am getting freezes just before the username button appears on the login screen. The Fedora logo at the bottom of the screen fades about half way in and then it freezes. Usually it releases after a couple of minutes, but sometimes it stays frozen. After logging in it does the same thing with the dash about half faded in. When it finally releases I am unable to click anything. It does not appear to be a trackpad problem because the arrow cursor never changes to a finger when hovering over a clickable link in a browser and other UI buttons do not highlight beneath the arrow as usual. When I switch from Wayland to X11 the delays are shorter and the clicking problem does not happen. This is happening on two devices, both MacBook Airs. On one of them the problem began immediately after upgrading from F37 to F39. On the other I installed a fresh F39 and everything was fine until I installed today’s update.

I have tried deleting ~/.conf/dconf/user as suggested for a similar problem in another thread. That seems to fix the click problem but not the delays.

Any ideas?

The cause of this turned out to be the Keyboard Backlight Slider in Gnome 45. As long as the keyboard backlight is off or above approximately 60% brightness all is well. Below that I get all the delays I mentioned above. It affects Wayland more than X11 and the problem persists across reboots. I assume that clearing the Mac’s PRAM (Option-Command-P-R immediately after power on) will also fix this since that will reset the keyboard brightness value. I also assume this affects only MacBooks.