I had the same problem! After a day, I pushed it below the surface and it still stayed in the top inch.
Low porosity hair can get you like that because it gets so dry, so you think "oh, my hair is drying out really fast" when in reality, it wasn't properly nourished in the first place.
Shampoos and conditioners that I have used and liked include:
Mielle Pomegranate and Honey (shampoo, conditioner, leave in conditioner)
HASK Argan Oil (shampoo, conditioner)
Shea Moisture Low Porosity (shampoo and conditioner, but this one may have been discontinued)
I have been using the Mielle leave-in conditioner regardless of what other shampoo and conditioner I'm using. It makes a WORLD of difference!
This is a list of oils that are best for low porosity hair. My favorite was a sweet almond oil blend, also linked below (I'm pretty sure it's the right one, haven't seen it at Walmart for a while). I used the oil for a refresh when it was frizzy and it helped a ton.
https://salonworthyhair.com/best-oils-low-porosity-hair
https://www.madeforlocs.com/products/locs-vegan-oil-spray-bundle
Using the right products changed everything for my hair. It is much silkier, much less frizzy, curls more nicely, and doesn't get too frizzy or too oily as fast as it used to.
Having a kid made my hair less curly and far more manageable in general, but that's obviously not a life hack option for manageable hair.
If you continue having issues after a couple of months, or if you just want to do it now, look into your individual strand thickness. Fine, medium, coarse. This can also have an effect on how products work with your hair. I am not as familiar with this aspect of hair care.
Glad I could help!!