Had the same setup in my last place, no outlets on that wall at all so everything ran off extension cords. I skipped the motion sensor ones for the same reason you're asking, figured they'd trigger every time I walked past and burn through charges. Went with plain switches and a two pack, one under the desk and one in the closet. Fourteen months later both still hold a charge for about a week if I leave them on low. The trick for me was not trusting the sticky pad, I used the little screws that came in the box on the desk side and kept the magnet strip on the light itself. Zero falls since.

Man that ground strap will get you EVERY time. Nine days though?? I would've lost my mind by day three for sure. The worst part is you LOOKED at it twice and it still fooled you, that's what really gets me. Sometimes those things look fine on the outside but are totally shot under the insulation where you can't see. Glad you finally found it before you set the truck on fire.