Is a 51% attack legal to do? Or is it illegal?

This is my first post in a long time, I lost my other BCT.org account and had to make a new one. I sold a few ASICS from BITSHIT (you know the company) after they screwed the mining market and havent touched my wallets in a long time. I recently checked Binance for the first time in two years, and see that Bitcoin is around 9K. Now it's down to 7. I am not here to FUD, I am here to beg the question: If Bitcoin never goes past 10KUSD again, and rallies up and down between 5-10K, what is the best course of action? Knowing (believing) the circumstances of never getting a moon mission again, what is firstly the community reaction? Second, will this affect Cryptocurrency adoption? Will this hinder or accelerate Crypto?

Sorry if this seems like such a silly hypothetical, but if it remains consist for the next 5-20 years then it is important to take into account Bitcoin and subsequently other Cryptos will never rally to the moon again like back in 2017 anytime soon. What is the best course of action to take here?