C section, Short breastfeeding duration, and Microbiome

Hi, first time poster. My daughter was born 3 years ago via c section. Unplanned- 36 hours of labor, 4 hours pushing, arrest of descent. She was large for gestational age, sunny side up, and tilted head positioning. Breastfeeding also did not go well. Did not latch so exclusively pumped. Baby struggled with painful GERD. Even though I had a good supply (actually an oversupply) we still had to supplement with formula due to poor weight gain. Weight started to improve. Also cut dairy and eggs. At 12 weeks old (still combo fed) baby started vomiting bile. Testing ruled out pyloric stenosis, obstruction, etc. Ped told us to stop breastmilk for a week (in case I had accidentally eaten dairy) and do thickened hypoallergenic formula feeds. Baby started to thrive so we decided to stop giving any breastmilk and switch strictly to formula. Thankfully she is a healthy happy toddler today! Since then I’ve heard on social media that c sections and formula feeding are causing negative long term health outcomes in people- regarding their microbiome. I’ve heard things as scary as contributing the rise in colon cancer to these things. It’s hard to know what to trust on social media. I just feel soo guilty like I haven’t done what’s good for my child. I’m losing sleep over it. Is there evidence of these things? How can I help her microbiome now? Thank you.