As always - isolate the problem - looks a fairly heavy set-up(?) but could you lift it from the wooden stands to verify that the noise is local to the slide table? (and not resonance from the stands)... I think unlikely - but a cheap test.

What's interesting with the video - from 02:40, the noise appears co-incident with the rotational position - would like the OP to verify this - from the short clip - seems to be the same bit of the motor coupler visible when the noise is at it's loudest - so is this a bent screw?, some mechanical foul along the motor/screw axis?

Does the problem remain with the (weight of the) camera mount removed? If not, does the problem remain with the bed fully supported? (can it be dropped onto the ground, or lifted onto a table?)

Next thing for me would be to remove the panels from the bed. Or to decouple the motor from the screw and to manually assess the freedom of rotation of the screw (decouple from the motor-side, and thumb/forefinger rotate the coupler)