"My issue is that the time it takes to model every element from scratch so that I can achieve the photo-realism I am going for, is insane. Things would be so much easier if ArchiCAD had some way of adding bevels to its geometry, or at the very least, creating its geometry cleanly so that I can add proper bevels in C4D."
and there are a few more things I would like archicad to do in this meaning of exporting to cinema 4D, and also I would like to have a cleaner geometry when you import from cinema to archicad.
I know these 3d Views are not Photo confusing realist, I have done renders a lot more photo realistic than these that you wont tell if is a photo or a render (can't post them cause I don't have the rights, they belong to a company I used to work that have the same vision of 3d views as you, trying to make renders super photo realistic) But now that you tell your goal I understand that you want to bevel everything. I also been doing this from long time ago and have had acquire enough experience as a 3d Rendering working. I've been through this of adding bevels, also putting every single tree in 3d, a lot of displacement (ohh, how much fun with that hehehe), people in 3d. and a lot of thing that you want to do when you want to get a very photo realistic render.
I'm not saying you don't know about modeling or 3d rendering, I don't know you, you probably know a lot more than me, I'm just giving you an advice based on my experience, You should consider this: Just do the bevels that you really need and will make a difference, that way you will save time and money. Try one view and make it with all the bevels you want to do and then render it again without bevels and show it to your clients to see if they pick up the difference unless there is an object very obvious that really needed the bevel. (I know some clients can do it, but majority won't), and I give you this advice because I don't know an easy and fast way to add bevels to every geometry exported from archicad, if I knew a way I would tell you with all my good will, and help you as most as I can.
PD: Do you really thing that adding bevels to those scenes will make them fotorealistics? I work with bevels only when really needed because I went through that path already and realize that it didn't make such a difference for the time you have to spend on it.