Automated Camera Operator - 7.2 Metre X axis 3.53 Metre Y axis 2.34 Metre Z axis

Hi,
My goal is to create a camera operator that replicates shots that I demonstrate to it. For that in my research, I need to create a 3 axis system at least.
The X axis needs to be 7.2 Metre X 2
Y axis at 3.53 metre X 1
Z axis at 2.34 metre X 1

for X axis, I would join two rails with flat butts together with one inversely positioned so the gaps are not the same. I also think maybe the y axis needs to be 2 instead of one.
The camera equipment (approx 3-4kg) sits on a moving carriage on a stable Z axis. I would use a displacement sensor and a breaking motor on the z axis, alongside stepper motors with belt drive on other axis.

I have discussed this with a couple other people who say that the load on the x axis might be too much for the belt since the length is long. That instead I should use steel ropes and a pulley mechanism.

What are your thoughts? I would deeply appreciate your help. Where possible please include the components needed and their configuration.
Any additional help is also appreciated.

Internet search for Bell-Everman servo-belt, specifically the "Looptrack" design. Inexpensive way to get really, really long travels without the drive system tension warping the structure.

Alternative is a rack & pinion, but that'd get really expensive for that much travel.

You could skip using linear rails and just use wheeled trucks that ride on/in aluminum extrusions. It won'd be very presice, but you can fiddle with it until it's smooth enough for good photography.