Black screen when resuming from suspend (Dell laptop, integrated graphics)

I'm running Ubuntu 20.04 LTS on a Dell Latitude 3520 laptop, with an integrated Intel GPU. I have a second Dell monitor connected via HDMI. These are the steps to reproduce the problem:

1. At the end of the day, I run Suspend and close the laptop lid.
2. The next morning, I open the lid to resume, and I get a black screen.
3. I press Ctrl+Alt+F1 and get the lock screen.
4. I enter my password, then get another black screen, but I can move the cursor and it changes shape, as if it's passing over clickable elements on the screen; so it's as if the screen is unlocked and my windows are still there, even though the display is black (except for the cursor).
5. Finally, I press Ctrl+Alt+F1 again, get the lock screen, enter my password again, and then the display finally resumes and I can see all of my windows again.

Unfortunately, I cannot seem to reproduce this issue unless I allow the laptop to sleep overnight. Simply putting it to sleep, closing the lid, then opening the lid causes it to resume from suspend without issue. So the problem seems to come from allowing it to sleep for an extended period of time.

I have not yet tested whether the issue still occurs without an external monitor connected.

I also observed the same behavior when this laptop was running the latest version of Pop!_OS, so it is not specific to Ubuntu 20.04.

Are there any known fixes for this problem? Otherwise, how should I investigate the issue further?