As a side question, is there a helper/tool where I can place a list of components (wifi chip, digital microphone, battery management components) and it outputs a PCB which could incorporate them?
As an amateur I always thought a “marketplace” of reference designs with criteria you could filter on (through-hole, easy to hand solder, pitch, programming, etc.) would be a great resource. You could even make an attempt at compatibility (I2C, SPI, # of GPIO pins) with certain MCUs. If something works in theory, let me pay the designer and get the schematic and footprints in KiCAD or other EDA.
Some printed circuit design tools have "auto routing." But in my experience for small, simple projects, once you've got everything else in place: The schematic, component footprints, etc., the actual routing is pretty easy. And nothing that I know of automates the whole process.