Hahaha SER! You can't merely just approach/talk to people, then make an introduction that you made wagers that totalled $65 million in two different casinos/sports-betting sites. Because even though you truly have wagered $65 million, I believe it would actually look more credible if you simply asked the casino how much their highest betting limits currently are for more serious punters.

To be frank, a serious punter might not want their total amount wagered be known by many people, especially in forums.
You are only telling the truth. When people are richer, they care more about their privacy and it is true not only for whales in gambling but in Bitcoin investment or any area in life.
I would like to add one more. Privacy can not be regained after you lost it. Like in forums, data will be archived by forum operators and even third party data scrapers can scrap data, posts and archive those information too. I agree with your about importance of don't publicly share information about wealth in any forum.
People share it can be are not aware about privacy, don't care about privacy or just want to show their wealth to satisfy their ego but later they will regret because as said, Privacy can not be regained after leaking and losing it on Internet.