Since upgrading to 23.04 I've noticed that my laptop no longer enters deep sleep (suspend to RAM / S0i3). One of the reasons I switched from Tumbleweed back to Ubuntu was that I had issues getting S0ix sleep states to work, but when I installed Ubuntu 22.10 it worked out of the box.
Now when I put my laptop to sleep the battery will just barely last overnight, whereas prior to the upgrade it would last at least several days. Can anyone suggest where I should start trying to diagnose what's gone wrong?