1mm is better but you did good using the 0.75mm.
The 11.2 amps tells me you are building a parallel LED cob\panel\strip based system. The current to each LED depends on the number of cobs\panels\strips you are using. To know how much current each cob\panel\strip receives: divide total current from the LED driver by the number of cobs\panels\strips connected in parallel.
HLG recommends using 18-22 AWG or 1 sq. mm solid wire
https://horticulturelightinggroup.com/pages/qb-optics-and-connectors.
Cree 3590 cob holders: use stranded 18-22 AWG (1 to 0.64mm) wire or 18-24 AWG (1 to 0.51mm) for solid wire
https://www.rapidled.com/ideal-50-2303cr/