Looks like a poor match for FDM printing. There's no orientation where the layers won't leave some part of this component very weak. In any orientation, it requires support material; in the suggested print orientation, it requires internal support material, which will leave rough surfaces on areas of the part that have to interface and fit with the ethernet jack.
Essentially doesn't really look like a 3D-printing project so much as an injection moulded part design.
This print would work fine. The forces cables are subjected to are far lower than the break point of the Z-axis layers. I would print in another orientation that had less interior fill.
Material used is rather important. PLA, which is probably the most common 3d printing material, is very prone to stress fractures. ABS on the other hand would probably do alright in this application.
Flex filament is probably too flexy. The trouble with PLA is that it essentially starts forming cracks at zero force. If you keep PLA under load it's only a question of how long it takes before it breaks. E.g. making a coat hook from PLA would probably work fine for a long long time, but one day it will break, Even if you just hang a coat from it and never touch it again.
> The component won't be undergoing any stress at all
It has a compliant clip that bends to clip and release; its entire purpose is to retain cables against being pulled out of sockets; and it is designed to press-fit around the body of an ethernet connector which, if it is not too loose or a perfect fit, will subject it to a continual stress.
Essentially doesn't really look like a 3D-printing project so much as an injection moulded part design.