Not enough squish on first layer, and/or too low of a flow rate. Slowing your infill speed down may help some too. The hex pattern includes a ton of movement where the filament needs more time to stick without getting pulled over the corners. Those errors stack up.
In complex designs, if I want the hex pattern for aesthetics, I actually build it in FreeCAD. It is just a couple of arrays. Use clones or copies of your parts sections, quickly make them solid, make a big block of hex, and use the solid copies as booleans to shape the hex block into whatever gaps. With clones, if you plan out the workflow, the whole thing is still parametric. Mess with the wall thickness of the hex, and then test slice it a few times until most of the hex patterns are solid continuous extrusions. Then you can let the slicer do a more efficient automatic infill elsewhere like cubic, but still get the hex aesthetic, and it will print the hex as high quality perimeters while still printing fast infill.