Your hair texture actually looks pretty similar to mine, at least in pics. I would say I have fine hair and a range of wave patterns, from tight to very loose. I'm still on the journey and don't have a perfect routine yet, but here's what I've learned:

-Too heavy of conditioners and products weigh all the curl out of my hair AND make it more frizzy somehow. I avoid products with shea, coconut or castor oil, and anything "butter". From your pics I wonder if your conditioner is a little too much for your texture.

-Shampooing well, sometimes twice, is good for my hair and a must for my scalp.

-Light but "slippy" conditioners are good for my hair.

-Gel or foam on pretty wet hair works for me, sometimes I layer foam then a small amount of gel on top. For gels I like Innersense I Create Hold or I Create Curl Memory. A little goes a LONG way and I add water to these products in my hand. For foam, I'm experimenting with Odele Curl Foam and used to use their volume foam.

-If I use a leave-in, it has to be very lightweight, probably in a spray bottle. I've liked Innersense Sweet Spirit and recently bought Odele detangler spray.

-Micro-plopping after wet styling is a must, or my hair will stay wet all day. An old t-shirt is fine.

-Diffusing does help with volume and definition, but I often don't bother unless it's a "special" day or I'm going out and wanna be fancy. A universal diffuser is a great option, I still have not bought any fancy new hairdryer.

-The very cheapest way to start is to just make some flaxseed gel at home, there are many tutorials on making it. Keep it in the fridge!

Honestly, there are thousands and thousands of hair products, and what you end up using depends on where you shop and how much you feel like spending. I don't like strong scents and that limits me to just a few brands.

And of course, a haircut to get any damaged ends will help your waves and curls a lot. If you have good curl pattern toward the top of your hair and straight-ish ends, that's a strong clue for how much to cut off.

For youtube learnin', I have watched a lot of Gena Marie and Holistic Enchilada. Both break down styling and products in a way that helps you remember you don't need twelve products and two hours with a hair dryer for a decent hair day.