Rotor ALDHU cranks seem delicate to set up and maintain

The Rotor ALDHU crankset is a nice piece of kit from an engineering perspective. It´s lightweight and allows to swap the chainring easily if you want to change the gearing or if you have to replace a worn out chainring. Also, I like the look of the Rotor crank. My problem is, the bolt that was holding the left crank arm to the steel axle loosened unnoticed by me. When building up the bike I torqued them to 40 Nm and the right arm stayed in place. When the left arm started to creak I found the bolt did not have 40 Nm anymore. I torqued it back to 40 Nm but probably it was too late in the game. The left arm is still creaking when I´m pedaling with a hard effort (while standing, sitting does not cause issues). I can imagine this could have been avoided by having an eye on the bolts. My personal learning (and I do not want to generalize), the Rotor cranks are delicate to set up and maintain. I´ve the feeling sooner or later I have to replace it for a different crank.