Buy a luxury watch with the BTC and then sell the watch. A Rolex Day Date (full gold) can be purchased between $15,000-$20,000. Many reputable dealers accept Bitcoin.
You don’t have to explain a piece of jewelry from the 1980s. It’s likely an heirloom and by golly, you didn’t want to sell grandpa’s watch but times are tough.
Anything else is going to be a huge headache. Stay with brands that are easy to sell (Rolex, AP, Patek Philippe). Don’t stray into any other brands.
I know someone that has done this twice in the last couple years. He also has Bitcoin from 9-10 years ago. There’s no reason to enter into KYC. The companies that have your data do not safeguard it. Look at what just happened with Coinbase. And you don’t want to make yourself the target of thugs that WILL kick in your door and torture you. And you don’t even have to be a millionaire either to be targeted.
I am against such financial schemes. Maybe 1-2 times it can be done, it all depends on your country and tax, but it is better to leave as few digital traces as possible and exchange cryptocurrency for cash.
It's better to consult with more knowledgeable crypto users, rather than reinvent the wheel.
I write a lot about European and American legislation, but I also chat with people from these countries, and they have no problem exchanging cryptocurrencies for cash, despite all the bans and restrictions.