“Elevating” your status from newbie to the next higher rank works solely by satisfying the activity requirements and merit scores as explained on this thread:

https://bitcointalk.org/index.php?topic=2818350.0

Finding sellers and traders here with 250K BTC is extremely difficult, if not impossible. Even 1% of those bitcoins is a challenge.

Double digit minus rates might make it more challenging. You might stand a chance with KYC-averse sellers or those who might have acquired their coins criminally. Legitimate sellers will not hesitate to use exchanges for near-market rates and payments via banking channels.

Curious sellers might probably also want to inquire about your motives. Not everyone offers to buy 250K BTC at any given day. Imaginative minds and the paranoid might even balk at the risks involved. An entrapment, just to give one example.