Intel have a slight lead for emulators, since most of those are single-threaded. Light 3D modelling as in Blender or Solidworks? You'll need anything between a good iGPU and a 1660 Super. If you do want to save money and go iGPU, I'd aim for a
Ryzen 5600G (or wait until the zen4 APUs launch in a few months, those are probably going to be amazing), because Intel's iGPUs are very weak, but if you're thinking dedicated graphics card,
this is what I'd do. The GPU is a little more than you'd strictly need, but it's not actually particularly more expensive. Much better value unless you find a cheap secondhand GPU. If you do want to look for a secondhand GPU, I'd aim for a GTX1080 or up, but with a length limit of just 188mm you're going to have a hard time finding anything worth buying. Bear in mind that the performance of the next generation is roughly comparable to the past generation one tier up, so GTX1080=RTX2070=RTX3060. It's not a perfect comparison, but it gives some idea what you should be looking for.