Good guide. Only issues: I had to use a metal tool (like a letter opener) to very carefully pry the case open as no plastic spudger was working, and then when i got to pulling the motherboard/battery assembly out it just would not come out for some reason (I did coax it out eventually). Otherwise very straightforward process. Hoping my Galaxy watch works reliably again! (Charging up now, but already verified it still works!)
You may need to use a small screwdriver or letter opener to pry the case apart. I found with two different spudgers I could not get it to budge.