Environment FUD refutation (just the one I personally link to most):

https://www.coindesk.com/business/2021/03/05/the-frustrating...

PoW security is a vector, and doesn't flip from secure to insecure at some specific point. A gradual reduction in mining hash rate doesn't render the chain noticeably less secure.

Feel free to fork Bitcoin and use it as an alternative. Please note that this has been done in the past, and will probably be done in the future. There is a reason why the economic majority remain with Bitcoin, even though PoW isn't energy neutral.