If it's going in something (e.g. dahl) I use the frozen stuff. If it's to munch on raw or as leaves then I abandoned fresh spinach ages ago - Kale is much more robust and (IMO) tastes better.
What I do is keep it in the fridge, but sealed from air and moisture by paper towels, in plastic bags.
I used to do this in huge bins, when I lived in the states and would get several pounds of it in a bag at Costco and would shop but twice a month. It's the only way to eat fresh greens on a budget, within that peculiar way of life.
@Gradually_Adjusting It's already wrapped up in a bag and littered with paper towels but it's basically like that scene in X-Men where the senator guy dissolves on the table 😭
Maybe it's just a problem with Asda spinach. My frustration spilleth over this lunchtime.