Or absolutely skyrocketing from the early 70s to 1980. Start dates are always important. https://onlygold.com/gold-prices/gold-prices-since-1972/ Gold is almost 20 times its high point from 1972...not too much different than the Dow over the same period.
Just making a side point, not a comparison of gold to BTC. Gold had one of the biggest rallies of any major trading instrument in the 1970s...it's not too surprising that it spent years reverting to the mean afterwards. It did make a new all-time high in 2011 (21 years later). That's better than the Nikkei has done since 1990...
I haven't sold Bitcoin, but I bought it. Before doing this, I surfed the Internet and was lucky to find a good guide on how to buy Bitcoin wolrd wide. I should say, it is easy to understand and use. Also it is mobile friendly, and I find it to be convenient. Hopefully, this source will be helpful for you.
Buying and selling bitcoin is pretty easy. Ill attach an article underneath here that you can refer to for understanding the process. And yes you can buy on margin and some brokers do protect your bitcoins through insurance policy as well. You just need to look for the right broker for that. https://www.digitaltrends.com/computing/how-to-sell-bitcoin/