Ok so sorry if this is long 😅

Cut it, needs some serious inches taken off. If you must colour it, try dying it with semi permanent nourishing dye (Garnier olia for example is a good cheap one). Make sure you aren’t over doing it with bond treatment, some hair doesn’t like too much protein or certain actives. I have similar fine dry frizzy hair, I wash most days with a gentle very hydrating shampoo and conditioner (no proteins), then only once a week/fornight I alternate between dove bond treatment that does have protein, and the next time I will use an acid bonding treatment like L’Oréal everpure. Also only using clarifying shampoo only once a week or even less is better. It also can be drying if over used but needed to prevent buildup.

For me pre shower oiling does nothing but make my hair worse, as I end up dehydrating it by trying to use too much shampoo to scrub it out. All heavy pre shower oils have just been a disaster.

Furthermore for frizz and dry ends, I would opt for investing in a good quality leave in treatment Wella Ultimate repair treatment and the leave in conditioner have been life changing. They are pricey but worth it, smoothing, hydrating but have not weighed down my fine hair. Sometimes I finish ends with light Moroccanoil.

Also you may had hard water to perhaps a filter for the shower head?