Re-selling luxury items from thrift stores. How would I best go about optimizing this? And is it a worthwhile venture?

So I’ve been on the lookout for a worthwhile side hustle that could make me an extra $150-$200 bi weekly for a while now. While shopping at a thrift store with a friend a couple weeks ago I was surprised to find out that many wealthy people like to drop off their used dress coats and designer clothes at the store rather than reselling them. Designer brands like Hugo Boss and Ralph Lauren were just sitting there with prices ranging from $20 - $50. And to my knowledge the store gets a new batch every other week.

I was wondering if there was anyway I could best go about upselling these items to potential buyers on marketplace and other resale sites. And if there was a way I could even start up a mini business doing so. What do you guys think?