I checked your website with onion site. You have two options to select the deposit type: Fast and Note.

With Fast option, there is a Receiver's BTC address. Why not implement it similarly as with Note. May you explain about it, differences between Fast and Note options and why only with Fast option, there is an entry box for Receiver's BTC address.

With receiver's BTC address and user login data (I guess your platform will store that data before one mixing is completed and even after that), it can be a risk factor for user privacy.