None of the current crypto is safe except Bitcoin. As long as the crypto is still changing both in terms of supply, from the PoW system to PoS and so on, then the crypto is not safe. This means that there is still a possibility to do something outside of our instincts, or there is still a possibility to be stopped by the running system. Likewise with the current stable coins that we consider safe with a value equivalent to Fiat. If the addition of the supply continues and suddenly they buy up most of the Bitcoin with the stable coins they are developing, then the price of Bitcoin will increase and the stable coins will drop because the amount of supply exceeds the needs of the exchange.
And what category of people do you think bitcoin is safe for? If you say bitcoin is safe for everyone, that's not quite right. Bitcoin can be dangerous for short-term investors because it is volatile. Many investors consider bitcoin a risky asset. A risky asset cannot be safe. So it's worth rephrasing your definition. Bitcoin is more reliable than other altcoins.
When talking about price fluctuations, of course all crypto assets are insecure, because they measure changes in value based on fiat values. When investors invest, of course they think about how far the project can survive.
Talking about crypto with various kinds of changes that occur in crypto, the SEC always handles, if there is a fundamental violation of the crypto, then the SEC sanctions apply. Can these sanctions apply to Bitcoin? Of course not.
Why do I say others are not safe, while Bitcoin is safe. Because it is clear who owns all other crypto, if it is not the owner who commits fraud, of course other parties will do something detrimental to the crypto project.