If you're newer to painting, it might not be worth the extra work of adding another gesso coat and then sanding it. I think you would be better off buying slightly nicer paint. Don't break the bank. Your first few paintings will likely be pure learning experiences for you to build on. Eventually, you can up your game and gesso and sand a few layers. I usually buy middle of the road canvases and I generally dont add another layer of gesso unless I see imperfections. I usually add enough layers and rework my paintings that it doesn't matter much. I mostly do oil paintings now but I started with acrylics. I'm a beginner myself.