In my opinion, while Bitmain did not make the trend to reduce the cost of equipment for bitcoin mining, it is best to withdraw 12 bitcoins to fiat because $ 80,000 is a very good performance.
I'd suggest the author to maintain the most part of his BTC and hold. Hopefully, now or then the price will rise again and he will gain more profit in USD.
If i were the topic starter I would remain 8 BTC, invest 2 BTC, and change to fiat 2 BTC. Of course it depends on how he earned this BTC and if he is in a profit if he changes to fiat.