@Dozymoo42 short answer, no. Walking more won't make you improve. Read up on the scandal of graded exercise therapy and MEcfs and why it was removed from guidance after making people worse.
It doesn't mean you won't improve though. You may do. You will have good days and not so good days, in any case.
It's hard to get your head around fluctuations. Some days I can do a walk. Some days I can't. Some days I can do a walk and feel ok after (no PEM). Some days I think I am ok and it hits me after.
With visible, the stability score probably won't mean too much until you have built up a few days of data. It took some tweaking for my heart rate zones too.
With work, I find stress shows up on my data but mental effort doesn't. I can WFH which helps but I can still get very fatigued from a lot of concentration and that's harder to see in the pacing. There's some short lessons in the app on each type of exertion.
Stairs are my biggest one and cleaning (oops). Sometimes I do what I call micro pacing...pause after a couple of steps and rest a moment before going again. It's better than going up in one go and spiking my HR.
Anyway, I think I may take another day at home before my journey. I was just a bit hopeful of avoiding the traffic on good Friday.