For the first question, it depends if you bought the fifty cars for $100 each, or if your basis is less than that. Cost basis is key here. And no to the second question.
The IRS has designed crypto as a property, so you are subject to paying capital gains (or claiming capital losses) whenever you sell, convert, pay or earn. Converting one crypto to another (or to USD) is a taxable event, while transferring BTC in one wallet to another wallet is not (since you keep the same property). Further details at https://www.coinbase.com/bitcoin-taxes#paytaxes.
If you sell a car for more than you bought it for, you do owe taxes on that. https://www.carvana.com/research/2020/03/what-to-know-about-....