How to keep my hair moisturized and not frizzy?

I have short-ish blonde hair, very light and very fine. As far as I can tell, I don't have any split ends and it's not super damaged, just really dry.

I do lighten my hair maybe once every 6 or 7 months, trying to give it time to grow and the natural oils in my scalp to repair it a bit. My hair is pretty light naturally, but I like to get it a shade or 2 lighter, closer to white, and don't leave the lightener on for very long.

However, I keep noticing that my hair is really dry, crunchy, and sometimes frizzy. I use all natural and moisturizing coconut oil conditioner, and leave it in while I shower, but it almost seems worse afterwards... (I know using the lightener certainly isn't helping my hair integrity either ☹️)

Any oils or other conditioners I can use that will help with the dryness? I'm trying to do my best for the health of my hair, but maybe I don't know as much as I thought?

***I shower once a day, and only use shampoo once every other day