How do I liquidate stock?

I have around 400+ of a product soon once it’s all delivered to my address and then I want to sell it off ideally in bulk and start over?

Sell the 400 units as one bulk job lot on Facebook groups like “Amazon Wholesale Clearance UK” and to UK stock buyers at 30-50% of RRP for a fast cash exit, instead of sending it to FBA and paying extra fees.