Opinions please - pets

I just saw someone on my timeline compare:

Pediatrician is making me switch to formula for a week because baby girl is spitting up and not gaining enough she only gained 4oz in 2 weeks even though I was feeding her every 2 hours religiously. He said I only have to do it for the week and then I can switch back to exclusively breastfeeding but omg we've done the formula for a day and her poop smells sooo bad and there's so much of it. 😷

⚫️QUESTION⚫️ what's the story with this stuff? At 9months, do we stop formula feeding and switch from formula to this? Has anyone used it? What do you think? FTM, and I'm learning as I go! Haha!

Is soy formula milk better than enfamil formula (cows milk)?

Im trying to be vegetarian and dont want my 3 month old drinking cows milk anymore. Would it be okay to switch??

So my daughter was on Similac Advanced.. But was switched to Sensitive.. Well its been over 2 weeks and they sent over something to WIC to have it changed on my checks. I haven't gone to WIC yet.. But now I think this formula is making her constipated.. She hasn't been popping much. And when she does she has a really hard time. Question is... Can it be the formula causing the constipation??