I think the distinction that maybe is lost in self care is this:
self care is handling a problem in the future. You are taking care of your future self. If you see a deadline incoming, self care is writing a sentence, or an outline, or gathering research materials. You don’t have to do it all at once, but you can get your foot in the door–or you can do it, and have it out of the way! Both are self care.
It is also self care if you have that deadline, but you have been working hard all day, and you are exhausted, and people have been talking to you, and you just need alone time. You could force yourself to work on the deadline, but if you can feel yourself starting to fray and fall apart, self care is taking a deep breath and giving yourself a moment of quiet playing a game or watching a movie and relaxing or sleeping.
Both are self care but have different ways to be applied. I see people saying that a lot, but remember: it’s the situation that changes the care method. Opposite action is important. If you have done nothing, do one small thing. If you have done too much, take a moment to yourself.