It's never a good idea to upload anything personal or confidential to cloud-based AIs, as many of them use your prompts for collecting or training purposes. If you want privacy, its best to run LLMs locally. If a site does not say that sign-up is required, then you can still use it without logging in, but you will have worse limits and fewer models.

Bypassing chatbot safeguards (aka jailbreaking) is against the TOS of most AI, so use them at your own risk.