For starters, German bitcoin exchanges already cooperate with the IRS so your name is already in their books. It's gonna be a matter of time for them to pick up the infrastructure and personnel neccessary to purge the evaders. At some point they will send out letters to people they don't have a tax report from and request them to reveal their trading history. And then, I guarantee, you will be in deep shit. That's just the case if you havent cashed out into fiat at all. If you did they will just look at your bank account and see receipts from exchanges, and then you are fucked even faster.
It's safer to wage war against Gomorrha than withdrawing your gains from german IRS.
implying I am dumb enough to ever even consider dodging taxes

Especially since you can avoid them legally. Americans only get tax cuts after 1 year. It's never entirely tax-free for them