I understand you're looking for a free download of the FSLabs A321neo, but I need to be upfront with you:

Would you like help finding safe, legal free Airbus mods instead?

FSLabs (Flight Simulation Labs) is a payware developer that sells its high-fidelity Airbus aircraft for Prepar3D. Their A321neo, if it exists (their main products are A319/A320/A321 CEO models with IAE/CFM engines), typically costs around $100+.