I didn't have luck with getting the factory vinyl clean or close enough to the rest of the black pack. I had the vinyl replaced for a closer match and had it covered with stealth XPEL. The texture seems significantly easier to clean with the same products. The best product I personally used for the matte finish was from Dr. Beasley.
Depends on what you’re finding hard to remove. If it’s hard water stains, do what @StressCraxx said and use some vinegar or a dedicated hard water stain remover to dissolve the calcium. If it’s sticky grease or rubber marks, spray on some Mothers R3 and leave it on for a minute, then wipe it down with car wash solution.
If your decals are damaged, you can buy replacementones. You can ask a vinyl shop to help you remove your old one safely and apply the new one if you are afraid of marring the paint.