I prepare the models of Artfletch in Cinema and cut off the smeared vegetation if possible. Where this can't be done, I replace the trees or bushes that sea visible in the picture with plants for DAZ-Studio. The same for Lamps or Railings.
If you want more cleaned surfaces, you can try to find something from noe3d. Of course his models have more classic themes.
In this model I have tried to smooth some of the corse surfaces. That is not always possible.
A cut out window with a replaced glass and a C4D-room in the back would have been nice to have some light in the background. Well, perhaps another time
As far as the free/payed models are concerned: I guess, the modelers who went over to FAB just would like to make some money with their products. Just go there more often - I still find some good models there every week.

I don't know how to use C4D but for the rest I do what you do, and replace items I don't like by Daz models....and I visit Sketchfab almost everyday...as a retiree I have plenty of time...well...when I don't hike in the mountains, the Alps near Grenoble. Thanks for the tip, I'll take a look at noe3D's models.

Correction: the name is noe-3d.at

That is exactly what I did in this rendering. Sometimes I cannot get the right values for the Depth of Field
and the f-stop value is higher than the Focal Distance value. But this time it worked.