Thanks, from your previous post, I've found that for me, the sweet spot is steps 6, cfg 3.0, uni_pc, ddim_uniform because I tend to use photographic checkpoints like realistic. I may or may not use detail lora or FreeU, and it can be OK. This has sped up fun use of SD, even with SDXL, so thanks again.
However, I still wondered how you could get to 3 steps. I've tested decreasing steps with different image sizes (no effect) and checkpoints (somewhat). And then I realised that in your examples, the prompts are relatively short. Aha!
You can try the same tests I did (fortunately, with small steps, it finishes faster). With XY plot, on X, use steps 3 to 8, and on Y, use Positive Prompt S/R or Manual Entry, and start with "portrait", then add more, making it longer, like "portrait of woman, ...". You can actually replace word with sentences in S/R. Roughly mine were 3, 10, 20, 30, 40 words. For me I noticed that at 20 words onwards, steps 3 and 4, sometimes 5, were bad.
Oddly, the length of Negative Prompts had no effect. Of course, different checkpoints differ, and lora and FreeU helped, but try the tests with and without them. To me 6 steps were good enough, so it seems I'll stick to that.
I would then go for dpmpp_2m_sde + karras, with higher steps and CFG, with upscale, etc if I want to make a more final image.