Genetek Electric Multiple Power Supply Adapter and Daisy Chain Connector, Add2PSU by (Black)

I know someone mentioned this in the comments but just to be sure, can a second one of these be used to join a second psu (total of 3 psus) ?

The 2nd psu powers on a fraction later then the primary and all the gpus on 2nd aren't being detected by my motherboard, how do solve this?

Does it matter which components are powered by each psu? for instance, should a matching gpu + riser all be in 1 psu, or is mix-n-match fine?

How many psu can I connect to this ?