I recently sent €100 worth of Bitcoin to Revolut where I had bought it back in December and the deposit came from the withdraw address and they rejected the "source of funds" declaration. Being Revolut's withdraw statement matching the address. I then zapped €200 worth to Kraken, swapped it to € and instant wired that to Kraken, no question about the "source of funds".
Imo the new law will see many amendments over the next 1-2 years as the EU continues their struggle to remain in control over the money and it will not be easy to turn BTC into cash if those sats come from a non-kyced stack of coins. A simple "I mined those coins in 2015" wont suffice.