Hello fellow wavies, i need your help!

I am a wavy girl from europe.
Back in high school I used to have waves that were easy to style and somewhat nice looking.
Now, in college, they are not as curvy as they were and very difficult to style. (Probably due to thiroid problems and hair dying, I don't know..)
I tried to deny being a wavy by brushing them out (too lazy for heat styling )

2 weeks ago, a friend gave me the tip to try silicone free hair products and my hair already looks healthier.
however, I want my s-waves back because straightening is so hard, but I just don't know how and I don't have enough money to try all kinds of hair products.

My current routine consists of washing hair in the morning with silicone free shampoo and conditioner (combing in the shower!),
and then applying some mousse and oil if needed and waiting for them to airdry.
But it just doesn't look right..

I think I have a 2b type, medium density, my hair is about shoulder length, medium to fine hair i guess and I think high porosity.

I already read so many posts on being wavy, but I just need a simple routine because there is so much information and I have no idea whats right for my hair type...

So I would be really happy If you could help me out!

please tell me if you need any pictures