Hi the Attiny library for Kicad is existing. Yesterday I checked that. Only is missing symbol for 7135 but that’s it not problem. PCb layout for AMC you can use standard library for that case. Thanks for link to Eagle tutorial. I am also new in PCB design and there are some specifics when you design LED driver especially like circle PCB and exposed circle contact points. Maybe I will try to make same driver in Kicad when watching Eagle videos.
One big advantages (dissadvantages for someone) which is unique for Kicad is that you can assign any footprint package to any component. In anothers PCB softwares any symbol component have assigned footprint. In Kicad you can have best from 2 worlds, when you create new device you can assign standart footprint to it and if you need you can after that easy to replace it with another package when you link PCB components to schematic.