I passed kyc and I do not regret , I do not think that something bad can happen to your documents , I think this wallet has a great reputation and it is unlikely that they will expose themselves
I've read that our personal data can be sold and can be used for things we don't know. This is quite reasonable because there are many projects that just disappear after the participants do the Kyc.
Yes, this is something very terrible if our personal data is provided free of charge to any project that asks to do KYC, I personally always take care if I want to do KYC on any project. Because we don't know what will happen to our identity when our data is in the hands of others.