Breastfed baby constipated

My LO is almost 5 weeks old and has been dealing with constipation pretty much her entire life. I’ve been to the GP many times, phoned 111 and spoken to the health visitor but no one has helped and several times I’ve felt like I’ve not been taken seriously. She’s clearly in pain and it’s causing her a lot of distress and I just want to know if anyone tried anything at home that helped their baby. She’s breastfed so I can’t add anything to formula etc. Please help as I’m at a loss and finding it hard watching my daughter in so much pain.

Things i tried:

Tiny bit of cool boiled water

Temperature up bottom

Bicycle legs

Stomach massage

(Also I know it’s normal for breastfed babies to not go as often but her gas stinks so bad and she’s clearly in pain. Also when she does go, it’s hard and stinks.)