I absolutely second that you need to both find out which ingredients work for you, and that you should only try one thing at a time!
This whole process is an uphill battle and I know it absolutely sucks to spend so much money and feel like you're not getting anything out of it. But I think figuring out what your hair wants will help you at least narrow it down so that you'll have a much higher chance at finding something that works for you.
So here's my hair routine, in case this gives you any ideas!
I'm a 3a with low/medium porosity, and with way more spirals and ringlets than s-shaped curls. My hair loves, loves aloe and I have a love/hate relationship with glycerin. Love in that the curl pattern and bounciness I get are unstoppable, hate because I get lots of halo frizz and using it twice in a row gives me hay hair. So I refrain, even though so many great products have glycerin in them (including, unfortunately, my $18 bottle of Curl Keeper).
So for my co-wash my HG (for four years now, my hair loves it) is Suave Naturals Aloe and Waterlily. Cheap and decent slip, and it's light and doesn't weigh my hair down. Plus, aloe!
For my rinse out, these days I'm using Garnier Sleek and Shine conditioner. It's CG and it's nice and thick and helps me get good clumps, plus it's cheap. I really like a lot of the Aubrey Organics conditioners, but since I'm trying to watch my budget and they're hard to find in the stores around here, I haven't used them in a while. But I do remember loving them!
For leave in, I switch between the Suave and the Garnier - it depends on my mood and what I have more of in the bottle. Sometimes it depends on the dew point/humidity or what styler I'm going to use (e.g. if I use KCCC I use the Garnier because it's thicker and makes it easier to scrunch out the crunch).
For stylers, I bounce between AG Re:coil, KCCC (I use a lot of leave in and a tiny amount of KCCC), TIGI Mousse (I don't know what kind - I got it when I was living in the UK and I don't even know if they carry it here).
I'm also trying some new stuff - I've been working on the same jar of KCCC and the same tube of Re:Coil for almost three years - and just today I bought Jane Carter Solution curl defining cream (I had a friend at school with hair really similar to mine and she swears by it, and I'm in the market for something new!) and Aubrey Organics Mandarin Magic (primary ingredient is aloe, so I'm excited to try it). I'm also really interested in trying FSG since so many people have great results, and I'm not sure where my hair stands on protein, so I'm also going to experiment with that now that the weather is going to be nicer (midwest winters suck the life out of my hair).
Finally, for gel, I absolutely, positively never go wrong with BRHG. It gives me great, great hold and my hair bounces and the crunch scrunches out easily.
For tighter curls, I use the AG Re:coil. For looser curls with more volume, I use mousse. For length and good curl pattern but firm hold, I use the KCCC. I top everything with the BRHG for second day hair.
I also do ACV rinses pretty frequently - I'm nervous to do them too often, but the water here is terribly hard - the white gunk build up on our showerhead is frightening and just thinking about all that in my hair... ugh.
So yes! Good luck - I know you can figure out what your hair wants, it's just a matter of narrowing it down. Even looking through the products you've already bought and separating out the ones that you definitely didn't like from the ones that maybe worked or worked ok will help you start to look for patterns.