That's what I heard too. SSD are apparently good for running your OS and/or some very demanding games, but not very good for storage. Just going with what I read/I've been told, though, not a PC expert either.
The one thing that I know for sure, though, is that SSD tends to be much more expensive than HDD. For my own pc, I recently switched to a 512 GB SDD for my OS and kept my old 2TB HDD for storage. I also definitely recommend an i5 at very least and an i7 for better performance, as well as a high RAM.
My own pc is an i7 with 12 GB of RAM. Can handle The Sims 4 with (almost) all expansion packs/game packs/whatever + a ridiculously high amount of custom content (~10 GB) on ultra settings with no lag, 3D editing softwares such as Blender and CSP/Photoshop with no problem. It does struggle on bigger canvases (like A3 sized paper or 600 DPI resolution), so if you're planning to work on a BIG canvas, I'd definitely recommend getting more than 12 GB of RAM.