Oh boy, you have a job on your hands. Stripping the top coat of wax should not be too hard. Wash it using a dishwashing soap like Joy lemon. Next step, do what should have been done in the first place. Depending on the severity of oxidation, & the application of a product that should have never been used, you may need either a mild compound or an aggressive compound. Go to a marine supply store to find what you need. 3M or Meguires have good product lines.
Do smallish sections at a time. If a mild compound does the job don't use the aggressive/cutting compound. After compounding, do it again with a cleaner wax. This will bring the shine back some more. The cleaner wax won't last long & you will be back to a dull finish in a month or so if you do not do the final step which is at least one coat of a top quality, yes it is expensive, sealer or pure wax.
I'm sorry. There is no instant easy way. I have been taking care of boats since 1981. Boats which are kept in saltwater. My time is valuable. It takes the same time to use a cheap product, which does not last, as an expensive product which can last a year. Me, I use the expensive stuff & only do it once a year instead of 2 or 3 times.
You might also want to invest in a rotary buffer as well. Your arms will thank you for it.