Taskbar / Taskbar blur, transparency, and color / Adjust taskbar transparency / [Settings]
Win11 variant... The default is 50%. Set some other value (I used 85%). The change is made and holds when you exit the configuration tool.
Problem: Reopen the configuration tool and open the taskbar transparency setting. The setting reverts to the default 50% and you need to set a different setting again.
Win10 variant... This issue doesn't happen. When you reopen the transparency setting, the setting that you chose is unchanged as should be the case.