Grrrrr, there was a miracle product from CHI that seems to be discontinued when I looked it up

I used to put in my little cousin's hair whenever she'd come back from the pool and wash and condition her hair. I would recommend a serum, but not biosilk, or garnier. I've tried these and they don't work nearly as well as the one I'm talking about. I heard the one from OUIDAD is good but I haven't tried it myself.
Nexxus Humectress is a good leave in, but it might have too much protein for long term use. However, it seems to give the illusion of healthy hair if you put it on before any styling product after you're out of the shower.
Hot oil treatments work well at giving shine and since you shampoo them out it isn't greasy. I'm about to get one of those heat caps and start doing
weekly deep conditioning treatments. I get so lazy about it though lol. I had to cut off several inches of heat damage last year, but it looked SO MUCH BETTER afterwards that it was worth it. I didn't follow up with trims and good deep conditioners so I have about 2 inches to cut off next time I go.
Also, Rusk Smoother is a great styling lotion. It's not perfect, but it genuinly does give shine, softness and definition.
Throw out that Pantene stuff though. I haven't tried any of the other things you listed, but the Rusk Smoother is $10 for 8 oz, and works WAAAAY better.
I would recommend a super gentle, moisturizing shampoo, followed by a good conditioner. I love the Pantene Relaxed and Natural ones, and if you have a decent budget, Bumble and Bumble Super Rich conditioner is great and you only have to leave it in a minute.
I saw a picture of your hair in one of your other posts, so I think this stuff will work great for you. After you shampoo and condition, towel dry, put the serum in, and then put the Rusk Smoother in.
Don't be afraid to put a lot in, because when it drys it will look soft and smooth. When I do it, I put it at the roots first, then I put it on the ends and scrunch. Then, I flip my hair to the left and put it all throughout, and do the same thing on the right. This way you get it everywhere.
I REALLY REALLY recommend the Rusk Smoother for you. Good Luck!