Im not from the US, and in other countries you must prove that the funds are from licit origin. If I don't have the trading history, im not sure how I could prove it.
Could you give some examples? Laws, guidance from tax authorities, things like that?
Your Livecoin trading history is just a spreadsheet from a dodgy foreign company. It's not really "proof" of anything. It's not an official tax document, so I don't see why you're dwelling on it.
I have no knowledge of previous experiences of people in my place in my country, so I don't really know what to expect.
Maybe you should ask for very generic guidance from your tax authority. No reason to give them details, but just general guidance about what to do.
In the US it seems it's different. In many European countries you must prove with proof that the money isn't coming from drugs and stuff.
This still doesn't sound right. Maybe if you were more specific about where you live, this could be proven or disproven.
There's also the problem of mixed coins. I once mixed some coins just to test, then I realized if I wanted to sell these coins, im not sure if it would be a good idea.
It sounds like you might be afraid of your own shadow.
The mixed coins are still your coins. You did nothing illicit. If you want to lose your private keys and donate the coins to the rest of us, feel free.
I need past precedents on the same situation to see what's going on when you are caught up in this situation. It's not a good idea to experiment in this field of being a testing ragdoll for the government's take on crypto taxes.
You might be waiting a while.