Depends on the forward voltage of the COB.
A 36v COB(? parallel strings with 12 diodes in series) like a CXB would be ~50w at 1,4A and ~75w at 2,1A.
A CXM22 is a 50v COB(unknown number of parallel strings with 18 diodes), at 1,4A it would be ~70w and with 2,1A it would be ~107w.
To get 85w from Luminus CXM22 you need ~1,7A per COB.
You could use a HLG-320H-48A to power 4pcs CXM22 in parallel. Each COB would get 1675-1750mA and the whole lamp would have up to 350w. That's ~38-39w per ft² and almost perfect intensity for indoor growing. And don't worry about parallel wiring its completely fine with HLG CV/CC drivers. These drivers have build-in poti's for voltage regulation(left one) and dimming(right) you can dimm the light within 50 and 106%/driver maximum.
Each COB or LED has its own forward voltage. For white and blue single diodes it's for example 2,7-3,5v, for red and deepred diodes its 2,1-2,6v and 2,5-3,0v.
COB's have lots of diodes in a series-parallel circuit. The number of diodes in series determines the voltage a COB need. COB's like CXB's have 12 diodes in series and need ~34-38v depending on the current running thru the COB. With high 2,1mA it's probably 37v at only 1050mA it's ~35v.
COB's with 18 diodes like the CXM22 or Vero29b need ~48-52v.
The current running thru a COB determines his brightness. The more current the brighter the COB. But you will loose some effiency compared to more low driven COB's. When you get 160lm/w from a CXM22 at 2,1A(107w) you would get around 17,120lm total. At 1050mA you would get ~51,5w but 180lm/w, thats 9.270lm but you need two COB's to get better brightness.(18.540lm from only 103w). The more COB's you use the better the efficiency of the fixture..