Its risky and dangerous to submit your personal information, such as your ID, to suspicious, unlicensed, or unregulated platforms. Without proper due diligence, handing over sensitive data to just any platform that asks for it is not only unsafe but also pointless, as it exposes you to potential misuse without offering real security or value in return.
It is only more dangerous if you KYC on suspicious, unlicensed, unregulated platforms whilst it does not mean that if you do KYC on legit, licensed and regulated platforms, you are safe and your identity documents will not be leaked.
Data can be leaked by many ways, internal sales or hacks from external people and you as a user can not control anything after KYC with your indentity documents. What you can control is before KYC on any platform, consider whether you should KYC or not, and eventually don't do KYC. It's the only way to make sure that your identity documents won't be stored on that platform's database and there is no risk of data leak by that company.