[Andreas Hopf]

When I compare these six methods (wall behind camera removed), all rendered 20 minutes (lighting setup in window title bar), constant dome plus sun comes out best in terms of three-dimensionality of scene elements, while HDRI plus emitter (plane outside windows, no glass/AGS) has the least noise. Also the physical sun looks better than the HDRI sun. What is best practice nowadays?

[Max]

i would go for dome+ sun + emitter, its the most realistic one, i dont care about noise, i do sl 22 (20 or 21 sometimes) on any render and then denoise it or retouch it if there are issues.
there are so many great denoisers out there that you should not worry about noise.

[Andreas Hopf]

Yes, dome and sun indeed looks best. We use Topaz Labs DeNoise AI. That is a very good fine-tuneable denoiser at almost no cost.