I was referring to the squishing of the filament indeed. I have two older UM2 printers with manual bed-adjustment, and I adjust it closer, so it is squished more. I prefer a nice glossy bottom, even if that causes a little bit of "elephant feet" sometimes. Not only does that stick better, but it makes watermark text in transparent materials (=inside the model, close to the bottom) easier to read.
In Cura, I usually set the first layer to 0.2mm. This too helps in giving a flatter bottom than 0.3mm, and gives better bonding.
I have no experience with UM3 or newer, so I ca