I like to play a colony for about a week. I want to get just into late game with a challenge then collapse. If it is too easy for me, then late game just drags out forever. If it is too hard then I don't get the same fun from mid game. I really like the thrill of starting a new colony, but just past the slog of early game. Starting around hour 3-5 it starts to hit a lot of fun up till about hour 25-30 or so. I want a good mid game with a bit of struggle, but not constant verge of death.
For mods I play with some basic quality of life add ons, but nothing extensive. The expansions have taken care of most of what I was adding in the past. I like dev mode for the one extra speed, but don't normally cheat with it. I do keep iron man mode on.
So, medium? Medium-hard? But definitely not hard or extreme.