Disclaimer: this is my own personal experience and some studies, so everyone is free to believe whether they are the same or seperate entities. I don't consider stuff like Qliphoth, since for me it is a toxic practice. I felt i wanted to do this post and share it here.
Satan: for me Satan has always been the most important God in my path, he's the one that helped the most and has been a comforting father figure in times of need. He gives strenght and comfort to his children when needed. I mostly saw his light but strong side as far as i remember - was bright like the sun. He is a very calm God with those who deserve his best and masters his own emotions, in contrary of what corrupted grimoires say about him being a war god. He goes beyond all that, he just reacts the best way is needed in the right situations, with his wisdom and power. He has compassion for those who suffer, but no pity for evil and submission. He is always there in real times of need if someone really needs him. If someone can do it alone, he will leave them alone not to make them depend on him. He doesn't ask to be worshipped, but it can be done, doesn't dislike it unless christian bowing down worship. He cares a lot about those close to him's well-being and will always be there for them in case of dangers and crucial times. He dislikes false morals said from unmoral people and only accepts logical morals (e.g dharma).
Lucifer: He's been a lot different in my experience. For me, Lucifer has been a dark spirit. He was stern, pushy and much harsher than Satan. He has no limits, he is the excess of freedom and wants others to be that way as well, with price of some suffering times. He hates weakness in a harsh way and is a very direct god. He can bring tough times. He can tell someone that is dumb if they are doing a dumb thing. He has these harsh ways. I can say the intentions behind it are for self development and growth, but it may not be for everyone. His energy seems cold, detached but protective with those close to him. He is good for those who think they are doing good by just submitting to others. He pushes someone to do shadow work and i can say it's not always necessary harsh in this, mostly uncomfortable. Lucifer seems to be depicted often in a false way, as just a lighty angel with no darkness and just all light and love, while he can appear as the opposite. He is the opposite of over-romanticized love for light, he actually seems to dislike this behavior and wants real freedom, facts. He doesn't seem to like offerings, can be done but are not his favorite things. He dislikes those who are scared of him. I've seen more darkness in him than light. All the things I listed are aspects of him and how his energy felt to me.
I hope it can be of help to those who may find answers on this topic and not to offend anyone else's different experiences.