"Seams" in first layer
Normally, such patterns are caused by too close printing to the bed (nozzle to bed distance too small), but considering the not fully flattened out extrusion lines (on glass I get a mirror shine fully closed surface) this does not seem to be the reason; you could try to increase the gap a little, in Ultimaker Cura this is very easily done with the Z Offset Setting plugin. Alternatively, you could use a little thicker paper to calibrate the bed levelling.