I am in the same boat. I've had oral thrush for over 4 years. I'm curious, were you dissolving the candex in water and drinking it or were you just swallowing the capsules? I was using a similar product called Interfase and it worked pretty well on the thrush when I poured the capsules into water and drank it. You could literally see the candida surface on my tongue and then it would just brush right off. I would think Candex should do the same since it also has cellulase and hemicellulase as the main ingredients which basically dissolves the candida cell wall. Unfortunately, I had to stop taking it though because my guts didn't like it too well but Candex may be gentler than Interfase.
I also tried most of the things you did but I was mostly just treating the surface of my tongue but more recently I realized that it is likely in my throat as well (which is why it is so hard to get rid of) so that is something to consider. Another thing to try if you haven't already is the Rx Nystatin. It seems to work for most people with oral thrush. Make sure you swish and swallow rather than spit it out because if you've had it awhile then it's probably in your throat as well and it will just keep coming right back if you don't get it all which is what happened to me the last time I took Nystatin. If you are sure it is not in your throat as well, then I would recommend thyme oil applied directly to your tongue and inner cheeks, it works very well for killing it on contact. The best way I found to apply it is dipping a Q-tip in coconut oil and then putting a drop of thyme oil on the end and then applying it. Always dilute it or you will burn your mouth!
Another thing to consider is drinking kefir. I bought some water kefir grains on Amazon because it's much cheaper than buying probiotic supplements and has alot more strains than you will get from any of the bottled stuff. It tastes good too.
Anyways, I have an appointment coming up with my doctor and they will probably give me Nystatin again so I'll keep you up to date if that works. Do keep us posted on your progress. Best of luck to you.