That would be illegal in pretty much any European jurisdiction - like court appearance illegal. And is also grossly in breach of the TTN Fair Use Policy.
As for dropped packets, how far apart is your gateway and your sensor? Too close and you will overload the receivers which will be unable to process the LoRa chirps successfully. Preferably 5m and a brick wall between them. Or a dummy load / 50Ω resistor on the device antenna.
For frequency plans, mostly people will use the recommended plan unless they know what the impact would be on reception & coverage for the RX2 window at SF12 instead of SF9.