Many people say "self care", when they mean "self coddling"
Self care means life admin - the grown-up stuff that no one else will do for you and will only benefit you once it's done
Facing up to possible debts and dealing with the paperwork
Sorting out credit cards or loans
DIY - there is nothing more satisfying than sorting out that thing that annoys you every time you pass/use it, but you keep putting it off as it's a faff/requires a trip to Homebase/needs the ladder dragging out of the shed
Getting a handle on the banking, pension, utility and work paperwork
Setting savings goals and setting up accounts for your savings
Housework, laundry, shopping, gardening
Starting or continuing a hobby
Working out, going for a walk or getting some other exercise
Possibly looking for a new job
The face mask and glass of wine in the bath by candle light is a little treat once you've done something you didn't feel like doing
Self care doesn't mean spoiling yourself, it means doing things that benefits present or future you. So creating peace of mind by ensuring a cleaner, less cluttered environment absolutely is self care.