LOL I would spend every single fiat I had into BTC and would never sell them.

I would not spend much in luxury, I would loan money from the bank, from the relatives, from friends, from possibly everywhere and loan from others. I would promise them better return than bank of their money they gave me. Once BTC would hit it's ATH (~$19k) I would sell them all and cashed out. I would repay all the loan and with the rest I would buy when price are down and sell when price at the pick every time.

Not to mention, I would again spend all my cash to buy BTC when the price was $3,200 few months ago.