So, my research continues. At this point I am way, way, waaaaay overthinking this one. The 3400G looks very tempting at the price point, $30 for ~8% more CPU power is not bad. The problem is the Wraith Spire (71mm) stock cooler which is much higher than the Wraith Stealth (54mm) cooler, not to mention the Wraith Max (81mm) or Wraith Prism (92mm) really complicates stuff. This made me research a few more cases, and I just realised the SG05-Lite exists as well.
That would solve one problem (allow me to use stock cooler), but with the 12mm extra cut in GPU length (254 vs 266), well… -_-;; So I started to compile some of the information I’ve gathered and ended up with a hueg SFF Ryzen Gaming guide, will post it soon-ish. The conclusion for me is pretty much, either I go with a Cryorig C7 Cu for the SG13 or a <250mm Navi graphics card shows up soon, in which case I go with the SG05-Lite and Wraith Spire stock cooler. It looks like money will finally be available come september.