I see your point. Of course you’re correct. Thank you for illustrating the process.
My interest in UniWB came after reading Photographers: stop clipping your highlights post here. However my flow is that I rather set WB first (I carry ColorChecker Passport in my bag) and then try to avoid highlight clipping. During my experiments and tests it occurred to me that what I need is actually flat jpg lacking contrast and punch. I used to use portrait mode in my Lumix camera but it is heavily processed image and in the end RAW image was always underexposed. After switching to natural mode and decreasing every possible setting I’m quite fine and results are predictable. I also set zebra pattern (highlight warning in live view) to 105%.
Problems occur when:
a) I change WP in DT
b) I still did not figure out whether switch on/off vignette correction in camera. After applying lens correction I can still have some blown highlight (pana 20mm f/1.7 vignette is like 2EV when wide open). However I do like vignette and quite often I do not correct it.
Thus I assume that UniWB will be my last step in this journey. I need to solve other problems prior that.
As they say: learn you camera 