This is a really great learning scene but do one thing at a time! I just read through the 14 previous posts Happy with the geometry? Bevel? Using 2.8? There’s a Bevel Node for materials; it’s buggy by blender.org admission but I’ve tested and it’s wonderful! Saves you on polys.
Lighting? Using portals? Good! Rays are terrible things to waste. Glass and reflections still do better with Cycles. Cycles does well with GPU, renders better in 2.8 with little tile sizes, bigger tile sizes in 2.79 - go figure.
When you go deep into materials, don’t toss PBR at everything!!! I’m a nasty skeptic in the minority so I say use hand-crafted answers to solve different problems. PBR is good and fun but a wrecking ball more than half the time. 2.8 now requires a Displace Node where 2.79 didn’t, so watch out for that when you’re looking at tutorials. Normals and Bump and such will change your lighting drastically.
Keep your polys even - I like your pick of image and I prefer the raw, higher contrast version too. Just rope your workflow in. You caught Blender at a weird time: 2.8 is extremely different and 2.79, though not in vogue, still has wonderful lessons to teach.