I have a super sensitive scalp and I'm trying to grow out my hair

So, I have about 2 inches of 4c hair. I have autism and used to regularly shave my head. I've always had a super sensitive scalp, crying anytime I got my hair braided. To this day I still do.

I was never taught how to properly take care of my hair as my mom didn't know how(she's white, has no experience with hair other than a brush and scissors) and wouldn't learn.

I have no idea what products I should use. My scalp always feels so dry and my hair breaks off so easily. It's always so itchy it drives me crazy but I don't want to shave my hair again.

I wash once every 4-7 days, use argon oil once a week, I use a leave in almost every day.

Any advice is really appreciated, thank you.