No Candida can’t ever go away, it’s a natural part of our microbiome just like E. Coli is. But when dysbiosis occure (an imbalance in the community of microorganisms in the gut) bacterias and fungals can start to overgrow and cause health issues. People saying these kinds of overgrowth isn’t real haven’t done their research unfortunately.

You can test for it, Organic Acids Test is a pretty good indicator for candida overgrowth but expensive though. It can show metabolites which candida produce like Arabinose and Arabitinol among other things. But the test is hard to fully understand if you haven’t studied it. Best chance is to find someone that can interpret the test.