Hibernate and suspend not working on Plasma KDE EndeavourOS

When I try to suspend the system or make the system sleep, the system currently goes to sleep, but when I try to wake it back up, it tells me that there was a shutdown request “EXT4-fs (device name): shut down request (2)”. But then it just hangs there and doesn’t do anything else.
When I try to hibernate the system, it goes into hibernation successfully, but when I wake it back up, it’s as if I rebooted my PC. Nothing that was previously open got saved.
I can verify that I definitely have enough swap space, so I have no idea what’s going on.
I have tried the solution listed here, and it had no effect: Sleep, Hibernation, etc. not working?