Thanks, I just replaced the CMOS battery and checked voltages. The original from factory battery was still at 3.1V. The new one was at 3.12V. I'm not sure that makes much of a difference.
So I went through the BMC web interface and what really did it was checking the "Time Owner" property which was left on "BMC". After I changed it to "Both", I was then able to successfully update and save the RTC time.
I rebooted and for the first time in months, haven't had to manually set the system time through desktop settings. We'll see if it keeps up from here on out 👍 (or if it will forever be in stasis at "March 26, 2023, 11:3...").