It seems like hair should be sooooo simple, ya know? But we all know it's "KNOT".

I never did anything special with my hair. In HS, it was long - and herbal essence with a vinegar wash brought out the red highlights in the auburn. Stayed like that for a LONG time. At one point in the 80s, I found a stylist who put the world's best spiral perm in my long hair... and I finally had "big hair". She left, I graduated, and I didn't do anything special again for years, while building the first homestead. Mostly worked jobs where there weren't expectations on meeting any dress code, you know? The PR firm was a little different, and what worked then was to find someone who was a wizard with scissors. When at the university, I landed on a woman who is, to this day, a friend of Hol's.
During lockdown, it grew long again. My bangs (part of the previous bob) grew out to where I could mostly pull them back with the rest of the ponytail. B never cared what my hair looked like - as long as I wasn't fussin' about it. Went back to my usual salon, a year after lockdown - and my scissors wizard was gone. I absolutely hated the haircut the new girl gave me. Despite my explicit instructions. Hol straight up told me she was sick of hearing me complain about the cut. So I grew it out a little more again... and found my wizard at another salon.
My hair is really fine, even though it's silver-white now. Except for funny streaks that are growing back in dark again - sorta a reverse Elmira look. LOLOL. It's naturally wavy - but not so curly. The fingers & air drying are the best (for me) at getting some volume. Yes, my wizard is good with a round brush and dryer - and it always looks smooth & classic when I leave. For about 2 hrs. Then the waves start popping out again. LOLOLOLOL. The waves have their own pre-determinded pattern of what they want to do. A cowlick doesn't help either (thanks daddy!!).
But, making lemonade outta lemons is my thing, and it's my hair. SOoooo... I have a theory of rationalizations all made up about my hair to free myself to focus on things that matter a lot more.

Like actual self-care, for one thing.
See, I think all these years, my hair was always the "real me". No matter the awful things my mom tried to do with my hair, no matter the "fashion" trends and social expectations, no matter if I was in a "I must look like them to fit in" phase... or I WRGAS (angry non-conformist phase)... my hair always did what it naturally WANTED to do. And it was always there, BUGGING me, to pay attention to my inner needs. It was screaming -- be more like ME and all will be well!!!! And I was doing my best to try to make it conform to whatever design idea I was obsessed with matching. Wearing stuff that looked - wrong - on me. But all that time, my hair was doing the "Samson" thing... it was magical, it was my strength & power, if I just stopped trying to make it be what it WASN'T.
Gradually I heard the message. Accepted it. And I noticed, when I looked in the mirror, even with the aging process - I look more like "me". In between washing, all I do to it is brush it - all forward, till any tangles are gone; making sure to massage scalp; then back down.
Hol's got really thick, mostly fine hair - I mean she could make a dog out of her hair, if she shaved her head again. It's shoulder length or below. Jess put layers in it for her, which helps lighten it and give it more wave & volume & texture. She usually twists it up in a bun, too. Forgets to brush it; it does knot up too. But she rocks it. Everyday - no matter how she's dressed. She sent me a pic of her on set yesterday morning as the sun was coming up. Overalls, boots, sleeveless T - hair bun - of her drilling through an 1-3/4 steel plate into the asphalt of a city street, to make one anchor for the car crash effect they'll film next week. She looked like a modern "Rosie the Riveter" - all backlit with the sun coming up.
IMO, after thinking about this so many years... I think it's when we forget to worry about what we look like, and are just ourselves (and comfortable with it)... that the real beauty of "you" can shine through. Even dirty, sweaty, tangled hair, etc.
For now, just brush your hair more often. Maybe try another brush - a wide, flat one with few bristles maybe? Look at all the pretty hair accessories - LOTS of really pretty ponytail holders, there are big clips, too. I liked combs for awhile. There are jewelry style bobbie-pins too. And the soft headbands are probably my favorite - long or short hair.
But start from what your hair wants to be - and work around that. Hugs.