I don't think it's empty words—self-love is a real thing that is achievable. I've experienced it, although not very much lately. I think it takes practice, or a drug experience.
By practice I mean a meditation practice like loving-kindness, where you sit and emanate love outwards to all living beings, including yourself. The traditional way to do this in Asia is to start with yourself, then people close to you, then neutral people, then eventually enemies. As the feeling grows throughout the meditation, it's like getting a roaring fire started. You cannot start that fire with enemies, because they are like wet logs. They won't burn on a tiny fire. But once it is roaring, they will go right up.
In the West, the way loving-kindness meditation is taught is usually by moving yourself to the end of the queue. It's no secret that Westerners have problems with self-love. So start with your best friend, or your pet, or any being it's easy to have warm feelings for. Then progress to other beings and finally throw yourself in at the end when the feeling is strong.
It can be hard when the pilot light of loving-kindness has gone out, i.e. you feel dead inside. When that happens to me I get tempted to have a drug experience, e.g. mushrooms, ketamine, etc, to re-light the light. It doesn't always work but sometimes it does.
I agree with you that well-meaning people deploy the advice "just love yourself" too breezily. But I think they do mean well, and it is possible with some practice. Best wishes to you.
