Darby Allin executed what is being considered the highest elevation kickflip EVER ... but unfortunately it won't go down in the history books -- 'cause Guinness World Records tells TMZ Sports it doesn't have any plans on recognizing the attempt.
Here's the lowdown -- the AEW star is currently a month into his journey of climbing the world's tallest mountain (29,031-foot peak) ... and after stopping off at Everest Camp 2, he decided to kill some time by doing a kickflip.