Have sorted out some fotos, since PS takes CR2(RAW) pics. Restarted the workflow (aligning cams, dense pointcloud, mesh, texture, export) Results as pics below and the result is much better now (even in Cura)
Haven't worked on the material at any stage yet.
Since i am a beginner at 3D in general my guess is the scanresult can be improved by some settings/changings (more contrast at taken fotos...) and some adjustments along the workflow, right? Main issue for me now is the size of the resulting model.