@TRATOON For smooth motion on the X and Y with our ExoSlide Ender 5 Plus kits (or any other setup) the goal is low friction on the slides, and decent belt tension. The ExoSlide carriages should all slide smoothly on the extrusions with the belts removed. The bearing treads should also all contact the extrusions (to prevent wobble), but not be overly preloaded as that increases friction. We have a guide install video on our website under Guides > ExoSlide Adjustment.
Are you using a metal or printed mount for the Hemera? If using the metal mount, ensure the washers under the M3 bolt heads are used. It should be snugly mounted to the carriage face.
Regarding the Z, the Ender 5 Plus can be over constrained at the ends of the travel where the Z rods don't flex. If you removed the Z lead screws, can the bed travel smoothly up and down by hand (especially near the top)?
Regarding belts, as mentioned above, the XY belts should be tight but not crazy tight that brackets are bending. On the X, I tension the X idler bracket with one hand and secure the bolts with the other. On the Y, I use a small screwdriver or allen key to pry the front idler brackets forward and tighten the bolts with the other hand. One last note on the Y belts, ensure they are not twisted when then return in the extrusion.
If all those steps check out, one troubleshooting step I would take is to reduce variables in the system, and temporarily install the factory hotend/bowen/extruder on to see if that cures it.