Do:
If you are mixing average amounts - your protection is better. More similar transactions like your - guessing is less reliable.
If you wait before sweep or spend - your protection is better. More delay time - more transactions that are similar to your.
If you deposit 6 mBTC and spend 4 and 2 separately - your protection is better. There are more transactions that can spend 4 mBTC than 6 mBTC.
If I'm correct, LoyceV sometime ago had shared one way to track ChipMixer input by grouping them into 2 mBTC, 4 mBTC or something which I can't exactly remember. Why don’t you instead allow users to have their desired input of any amount; not tied with 2 mBTC, it can be 0.00256 BTC as well. I'm not sure such things existed in ChipMixer or not but I can't remember exactly as I had checked out long ago.