I run EnOS + KDE Plasma on a Dell 7480 (kernel 6.12.24-1-lts), closing the lid correctly triggers suspend & it enters hibernate after the specified duration.
It was 
smart of you to check for lid events with journalctl -u systemd-logind | grep Lid, doing same on my Dell returns:
Mmm dd hh:mm:ss hostname systemd-logind[###]: Watching system buttons on /dev/input/event0 (Lid Switch)
Mmm dd hh:mm:ss hostname systemd-logind[###]: Lid closed.
Mmm dd hh:mm:ss hostname systemd-logind[###]: Lid opened.
...etc...
Perhaps that is where we should look for root cause, maybe the “Lid Switch” system button isn’t sending an event or it isn’t being watched?
I rebooted my Dell on kernel 6.14.3-arch-1 then tested lid close/open - it correctly suspended & resumed.
When I checked output from yay there are indeed kernel updates available (for my Dell):
core/linux 6.14.3-arch-1 -> 6.14.5-arch-1
core/linux-headers 6.14.3-arch-1 -> 6.14.5-arch-1
core/linux-lts 6.12.24-1 -> 6.12.27-1
core/linux-lts-headers 6.12.24-1 -> 6.12.27-1
Which kernel are you using, can you try booting LTS to see if the issue persists with it? If you need to install LTS don’t forget headers:
sudo pacman -S linux-lts linux-lts-headers
& update GRUB if you use that:
sudo grub-mkconfig -o /boot/grub/grub.cfg
or if using the default installed systemd-boot in the default configuration then IIRC the new boot entry should be automatically detected & managed, but here are 2 relevant links worth reading:
https://discovery.endeavouros.com/installation/systemd-boot/2022/12/