On days where I have close to zero motivation to workout, is it justified to skip my workout? What’s a good way to feel accomplished in those times?

On days like this, listen to what your body is saying. Are you unmotivated because you are physically tired? Are you unmotivated because of frustration from work or home? Or are you unmotivated because of the workout itself?
Taking stock of what is going on in you, allows you to decide what is best. If you are physically tired, the best thing in that moment is to rest. Something the body needs just as much as exercise. But if frustrated, exercise can help reduce that, so consider going and maybe doing something different from your usual.