Interestingly enough, as expected I have a German Tüv allowance paper that came with the pulling bar that states that the towbar is intended only for mounting a bike carrier or a towbox with a max vertical pressure of 60kg.
AND you should know that the BOSSTOW towbar hitch as a whole is approved for pulling 11.6 kiloNewton (1160 kg) which is more than the Atto3’s (in NZ) allowed 750kg. The maximal vertical pressure that the BOSSTOW hitch can handle is 140 kg. This hitch is well-oversized which is OK by me.
I am not worried at all about the sturdiness of the hitch, it appears to be a strong enough construction that is capable of handling much more than I will ever need.