Baby spits up excessively! Any ideas?

My baby spits up more than the norm. Sometimes I can barely get her to my shoulder to burp her before it comes back out. I experienced this with my first; however, by 2 months she was gaining weight like she should. Now with my second, she hasn’t gotten any better at 2.5 months. I elevate her appropriately, burp half way though the bottle, keep her upright as recommended, etc. I only feed her 2.5 (recently increased) ounces at a time, and every 2 hours since she’s also having weight gain issues due to the spitting up. She does sleep well at night so I avoid having to wake her, which I will have to stop. Someone recommended taking her to a chiropractor as it helped their baby stop spitting up or having reflux issues and someone else said that when they mixed their breast milk with formula; their kid stopped spitting up. Has anyone tried either of these methods to help an excessive spitter? Mine isn’t bothered by it but it is prohibiting her from gaining weight. Our pedi wants to order blood work and X-rays to rule out any internal issues but they will have to draw her blood through a needle in her arm and I’m trying to prevent that. Any insight is appreciated. Thanks!