I can't make you love your hair, but honestly don't set yourself apart from us - many many of us spent years hating or at least disliking and trying to ignore our hair or trying to iron or relax it into submission. I wore a ponytail 24/7 for years and years!! Plenty of people here straighten some of the time at least, but try to limit flat ironing. There are heat free methods like wet wrapping, you might find a well done keratin treatment is healthier than frequent flat ironing when you have grown out the damage.
Unless you can see someone's hair without all the silicones and under the microscope you have no idea what condition it is in. Much of the damage done by flat irons is to the core structure of the hair, the high heat can literally melt certain silicones onto the hair forming a plastic coating, The seductive thing about flat ironing moderately damaged hair is that it makes the cuticle lie flat, so hair can easily look healthier when it has been ironed. I think it's also highly relevant that the YouTuber wears her hair curly often for videos, which 'rests' her hair. Obviously we don't know what she does with her hair when not making videos.
The thing I learned when researching damage is that it is cumulative, so heat styled hair is more vulnerable to peroxide damage, and colour treated hair is more vulnerable to heat styling and so on. My damage was colour and mechanical, I am not prepared to quit the colour so in some ways similar to you. What I did do was thoroughly research exactly what colour does to my hair at a structural level, so I am doing it with eyes WIDE open.
What I ended up doing was changing the way I approached my colour, I use a totally different much less damaging method now. I didn't choose to go wavy/ curly, I was shocked and forced into it by realising just how many broken hairs I had around my face and at the back of the head. Even then I didn't see the full picture, two years on I still have random short tufts at the back which I strongly suspect was mini clumps I'd pulled out at the roots with rough treatment. And I didn't even have good hair whilst I was doing it, doh!
Hat and pillowcase sounds great, you are one step ahead of many curlies there!! Combing when wet stretches the hair, how much damage that does depends on technique and product. Be sure you are using a very wide tooth seamless comb, be really gentle don't pull at all, work on wet conditioned not damp hair, if the comb doesn't slip through your hair like a knife through butter on a summer's day you should stop.
I know it sounds nuts but the right conditioner is an effective cleanser, think of WEN or L'Oreal and Pantene making cleansing conditioners. This is because there are cationic surfactants
and fatty alcohols in a conditioner. These are emulsifiers
which means they can mix oil (sebum) with water. The cleansers in shampoo are usually anionic surfactants
so they are a more powerful 'relative' to one of the key cleansing ingredients in conditioner.
A lightweight conditioner (not too many oils, no silicones) can cleanse really greasy hair after you have been sick in bed for a week, even remove a heavy coconut oiling. Technique and amount of product is important, there are videos on YouTube. Conditioner washing cannot remove build up of many silicones, certain butters or polyquats so it's important that your other products are compatible OR that you carry on using a gentle shampoo every week or fortnight.
Lifestyle healthcare is what I do for a living - if you are not getting enough protein there is one change you can make: start eating oily fish (salmon, trout, mackerel, sardines, herring, anchovies, fresh tuna counts but not canned). This supplies protein, but also omega-3 essentlal fatty acids, vitamin D, haem iron and a raft of other vitamins and minerals. Oily fish is massively more nutritious than any land animal meat and is the only realistic source of long chain omega-3s. You don't need large servings of protein - actually the body cannot process and utilise that - your body needs it little and often beginning with breakfast.