How to stop politely tell people to shut up

Now my daughter is 5 months old. She's very social, always giving strangers a cute look and smiling at them and putting her arms up wanting to go with them (she will if I let her, which is another concern). Strangers are always flirting back, saying she's cute or whatever and I don't mind that in the slightest. I always get the one person who pisss me off though. Someone told me I'm

Spoiling her for holding her in my arms and not putting her in a stroller. Another person told me to put a bib on the poor kid because she's teething. One person even got mad at me for not breastfeeding even though I am??? Anyways, in each case every person thought it was okay to criticize me and tell me their life story. Usually when I'm out in public I just want to go back home ASAP so it really irritates me when people make unsolicited opinions and sit there talking to me for 30 minutes at a time. I thought that flat, polite responses would do the trick but it has not been working. I've even said "I'm

Sorry but I have to go" and they'll ignore me. It's awkward AF to just plainly walk away because they'd probably remember me.

Is there any way to tell them to shut up politely???? Help me I dread leaving my house