To terminate three single core, 240 sqmm Al/XLP/AWA 33kV cables between two NXPLUS switchgear, as you can see in the attached picture, it has rubber sleeves at the cable entry, is it better to use brass glands instead, in order to keep the armor connected to earth, or this is not advisable?
The gland has two functions. It is to act as a transition point for the cable to allow it to remove the protective insulation and the second is to fix it so that in the event of a fault, it does not move.
The termination enclosure has 2 functions. It protects all the equipment and terminations from exposure and accidental contact but the second and more important function is to keep an explosion contained within the termination cubicle.
If there was an incident and when you are signing for the installation using the Taking Over Certificate, part of the specification would have been that the installation complies with various standards and local requirements.
If your termination method conforms to all of this, I would not change it. The installation team will have found the fastest, least expensive method to comply. If you are unhappy or doubtful about the installation request the standard and the certification of the person that conducted the installation.