Hello,
My issue seems to have been fixed with the help of a knowledgeable (and perceptive) person.
It turns out my system BIOS was using local time instead of UTC time, and linux, for whatever reason, wasn’t automatically setting BIOS to UTC time.
I do also dualboot windows, but I hadn’t booted into windows since a few weeks before installing tumbleweed.
The fix:
I forced windows to use UTC time with reg add HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation /v RealTimeIsUniversal /t REG_DWORD /d 1
I rebooted into windows and then rebooted into linux. Linux was still using local time, even though BIOS was correct.
I ran timedatectl set-local-rtc 0 --adjust-system-clock and then rebooted.
Problem solved!
A side note:
Turns out I was also using proprietary NVIDIA drivers instead of the open NVIDIA drivers.
Fix:
zypper in nvidia-open-driver-G06-signed-kmp-meta
zypper inr