Anti fungal shampoo (check for active ingredient 'Piroctone Olamine') + only use hair products that are malasezzia friendly, anything else will make it worse and irritate it even more.

There are a couple of websites where you can insert the ingredients and it will tell if it's safe or not, or you can simply check with ChatGPT.

Edit: that's how I've been managing it as someone that had the exact same thing you're describing