A billionaire is about to [re-]become the unfettered god-king of Amerikkka (this time with more kakistocracy!!), I wouldn’t take that (current && temporary) barrier as a blocker to innovation. Get a rough prototype together now and you may corner the market while we’re still here.
> catalog of rare antique pieces or collections
Solutions already exist for a small and well-serviced market; owners of such pieces and collections already know who to fan out to and actively do, that’s why Sotheby’s etc exist.
> something that connects them with people of the same social status
See PoNeWo and PoNePo mentioned previously.
Assume that, if it’s buyable by the wealthy they already have an app for that — or, rather, their personal assistant, concierge, secretary, congressional page, rent[boy|girl] has an app for that — what you need to think about is opportunities for experiences they cannot (currently) buy.
Which brings us full circle to progressively more dangerous games.
Here's a great example of a web app https://www.photopea.com/ that copies photoshop and is currently making 2 million dollars.
First, the rich/wealthy are not paying for a “Free Photo Editor” that’s an alternative for Photoshop. They are also not paying for Photoshop. That’s not how you get and/or stay rich/wealty. Instead they pay someone else to use Photoshop on their behalf.
Second, building a better mousetrap is not how you attract the rich/wealthy; in an extremely small minority of cases building an actually better mousetrap is how you become rich/wealthy, specifically by selling it to the not rich/wealthy. In most cases you become rich/wealthy by already being wealthy (see PoNeWo), these days mainly because your forebears are rich/wealthy or, rarely, talented (see PoNePo).
If you want to sell to the rich/wealthy, the key is to give them someone they can hunt without consequences; for your purposes, ideally, that’s someone else, but it really depends on how much money you want and how fast you think you can run.
I've never seen an issue covering photoshop alternatives.