Just a note that you probably don’t want to scale your z for this (or hopefully ever). You need to slice your model in cura at 0.2mm layer height.
The key things to dial-in for tuning first layer are z-offset and extrusion multiplier. Z-offset will define how accurate the distance between the nozzle and the bed is. If you’re printing 0.2mm high layers, your print should start with the nozzle ~0.2mm above the bed. If you are also trying to get accurate printed layer heights, extrusion percentage scales how much plastic is extruded. This varies by filament. To get accurate layer heights your printer needs to be “spreading” a consistently thick 0.2mm layer of plastic.
I might dial the above in with one of the small squares you are printing, and then work on the larger full bed test.