Recently I have started to test the "Tiled KSampler" custom node and to my surprise it got me better results than my Ultimate SD Upscale workflow with the same parameters, it is better at adding finer details and the seams are almost invisible.

For Hyper realistic landscapes and portraits I still use the SD 1.5 + Tile ControlNet on Ultimate SD Upscale, but for everything else I like this workflow better.

Obs. I only posted zoomed in examples as the high resolution images are 65.5MB and there's a 20MB limit per img.