There's only one word for that noise.!!. .Grrrrrrrrriiiitttttyyyyyy bad. It should be more Swissssssshhhhhhh than growwwwllllllll.

It's not unusual to feel resistance in the movement because that's the preload in the linear bearings and ball-nut, however, the sound should be more of a Swish than a growl.
So absolutely got something going in there and I'd tip it's the ball nut doing most of the growling.

I would remove the bolts that attach the carriage to the ball-nut and move the linear guides on their own. This will identify the bad guy.

I can't quite see on the video but do the rails have bolts holding them down in every hole.? If not then you could also have an alignment issue which is compounding the issue. Linear guides are great when set up correctly but unfortunately because they are precision components they don't accept sloppy fastening or poor alignment very well and will binding and can growl if the alignment or parallelism is out.

Time to move onto the next phase and take those bolts out of the ball-nut. It should soon become clear where the problem lies.