Im interested in trying out a overcooked speedrun, but it doesn't seem like the category is very active. Can anyone help me with understanding in what areas you can actually save time and which areas are basically just auto scrollers, this would be really useful so I can know what areas to actually look at for a speedrun instead of watching the whole thing and trying to figure it out myself

The time saves that aren't just better movement on the map or levels are: Kevin Skip (saves more time when not failed at all), Skipping the new recipe pop up earlier (Chalkboard skip), Serve timer levels, cutsceenes or conversations and the final level. Those are the ones i remember and that are more significant then simple techniques that barely save any time. If you need any more help i have my discord linked to my profile here.

depends on the run any% or 3 star, for kevin (skip all the kevin on any% and know how to do it) also knowing how to unlock all the kevin levels for 3 star.

Bust like Avex said a lot of it is just skipping conversations, pop ups, getting the first order out on certain levels, and making a good run on the last level, its the only one that ends when you finish the last order so you can save bunches of time there. For me personally my biggest saves was the first recipe and last level, and its still what I'm working on the most right now.