Unless you plan to do a lot of traveling, the Platinum is not worth it.
1 - You do not need a Gold Card, or any specific card, to get a Platinum Card. You should easily qualify for either, given the info you included in your post.
2 - Platinum is not "better" than Gold. Rather, it is better for certain uses, while Gold is better for other uses. Some people think it's worth having both, because their benefits don't overlap very much. Gold is very rewarding for accumulating points for either dining out, or buying groceries. Platinum is largely about hotel status and lounge access, and paying for travel.
3 - With either Gold or Platinum, you should read up a bit on what to do with Member Reward points (MRs), which is the currency that Amex gives you for using these cards. Generally speaking, they are best used for travel. They are not easy to convert to cash for a good value.
Let us know what you decided to do. Good luck!
I can tell you,
I got the Gold card in the 1980's and I sure as heck did not even know what a Platinum was back then.
You got some really good answers upthread.
With your scores, you will have zero issues being approved for Gold or Platinum. The key as others mentioned is to get the card that best fits your spend and lifestyle as they are very different cards. For some of us, both make sense. The other important thing is that when you decide to get one (or both), make sure you do research and find the best Welcome Offer available for the card, as they can be earned once in a lifetime. You don’t want a 50k Membership Rewards offer if there is a 100k offer available.
As for “black,” there have been no known offers within the credit enthusiast community extended for the personal Centurion Card in the past few years, even for those regularly spending many hundreds of thousands or more per year. There have been a few known offers for the business Centurion Card. It is correct that the card is by invitation only, and they are not very common. I’ve personally seen a few, but even most celebrities and athletes that have these cards are authorized users on their agent’s card and are not primary cardholders.
As for “black,” there have been no known offers within the credit enthusiast community extended for the personal Centurion Card in the past few years, even for those regularly spending many hundreds of thousands or more per year. There have been a few known offers for the business Centurion Card. It is correct that the card is by invitation only, and they are not very common. I’ve personally seen a few, but even most celebrities and athletes that have these cards are authorized users on their agent’s card and are not primary cardholders.
Are you me? 
You might want to apply for the Platinum, first, before going for the Gold in case you decide you either want both or only the Platinum at a later date within twelve months of having been approved for the Gold. AMEX approved me for Gold in August 2019 with a FICO score 670 only to read in the community that I was likely eligible for the Platinum, which I wanted even more than the Gold given my weekly corporate travel.
AMEX denied me for the Platinum and the recon call advised a wait period of six- to twelve-moths before applying again. I wrote a letter to AMEX requesting a reconsideration given that I was AZEO with a FICO just above 700, but AMEX instantly shot back a curt denial letter.
I check the pre-approval page on my account every week, but no luck. I've been pre-approved for months to get the AMEX Hilton Aspire, Bonvoy Brilliant, and Delta Reserve, but I really want the Platinum for the lounge access in addition to the Gold for groceries and restaurants.
The waiting period has been frustrating, but it'll get ten-times worse once I start showing pre-approved while waiting for the 100K MR offer to someday arrive in the mail in lieu of accepting the 60K MR offer.
I regret not having applied for the Platinum, first, as the stars were aligned on the night I was approved for both AMEX Gold and Discover.