Tax efficiency is better phase than tax avoidance, but still pay your taxes! don't forget fatca and crs regulation, meaning you or your exchange will most likely declare your assets to the tax authorities.
Amount of tax also depends on your jurisdiction and accounting methods.
If you are concerned about it, a local tax professional can provide you advice in writing, which if you rely upon, will be proof of any intention to evade taxes.
This is why paid advice is worth more than free advice from internet lawyers, (who are not your lawyer).
Having provably no intention to break a law means that it is not going to be a "criminal" problem even if you are wrong, at most it would be a civil fee.