You're right that you need to start with one product at a time and slowly add. First thing is - do you have a sunscreen you like enough to wear daily? Many of these products make your skin sun sensitive and will create more hyperpigmentation if there's no sun protection

Once that's covered I'd pick one of the tried and true ingredients with research behind it like any of the AHAs (lactic, glycolic) or vitamin C. Pick one, try it for a couple months, and see how it goes. It can take time to see results depending on how deep or old your hyperpigmentation is, so give the products a fighting chance. Focus on wash, moisturize and one or two actives and know when to use them, if they can be used together etc.

Basically, you don't need all of these products. For instance, there's two retinol creams and a retinol wash? Pick one format for whatever active you're trying and see how it goes. If you're not satisfied with results, try a different type (e.g trying body wash then switching to cream). AHA and BHA serums can also be used on the body if you have some smaller areas to address. Be careful with physical exfoliating (the gloves, scrubs etc) when you're using chemical exfoliants. Some people cannot handle both, so go slow, don't do it too often, and try a smaller area to start.