Check your
HOOD.
Trust me.
I recorded video here:
https://youtube.com/shorts/bFptN89x0UY?feature=share
Sharp turns at slow speeds usually replicated on uneven surfaces I would get a clunk noise, or a knock, or creaking sound from what I thought was the front driver's side suspension, or steering column. Had my X5 in for service to the dealer 3 times in the last 6 weeks for inspection. The second time they replaced the tie rods per a service bulletin that did not fix the issue. The most recent and third time it was in, this time taking a full 7 days to try and resolve it, they did nothing but re-torque the front suspension components and finally concluded the sound is normal as they have not ever been able to actually replicate it.
Well anyway, after continuing to hear it and feeling gaslit by BMW, once I got my X5 home I just started pushing up and down on the driver's side over the tire to try and replicate the sound. I was immediately able to hear it coming from the hood. I recorded it and drove it again and was able to confirm that it is indeed the clunk, knock, creak sound I've been hearing. I can grab the hood and push / pull up and down and it makes this sound every time.
It makes sense now why this has been a mystery. The focus had been on inspecting the suspension and steering column, while it's the hood making noise when I suspect the frame flexes.
I can't say how relieved I feel to pinpoint it, and I hope it's as simple as this for all those who also have a "mystery noise".
****UPDATE****
Scheduled service with the dealer 4/15. They replaced the weather trim on the noisy side and also applied a lubricant to the bonnet seals under warranty. Took a few days for them to resolve the issue but happy to report the noise is gone.