Of course, you do not want to copy other artists’ work. Besides violating copyrights, it’s just unethical.
But why not learn from copying? Many artists paint old masters paintings just to learn how to do it. And you do learn a lot. As long as you aren’t selling it, or passing it off as a real old master,
I started studying art in 1963 with an extraordinary illustrator/fine artist named Morton Roberts at the National Academy of Design in NYC. I soon forgot about commercial art. Roberts fired up my desire to paint and succeed as a fine artist and I have never really left that path. But I did change my viewpoint on style and content.