the 1P2C strats look complicated, but are they really? also how much time do they save compared to just 1 controller

I can't really give a concrete number on how much time all the strats save, as there is so much variability between runners. Some 1p2c strats are necessary for all runners imo. Examples would be like the levers in Count Dooku (GC exclusive), both 2 player warps in Chancellor, the ramp in the first room of Theed, etc. You can get away without doing smaller 1p2c timesaves like in Negotiations, Kamino, etc. But it becomes a subconcious effort once you play enough that it shouldn't be a problem playing with 2 controllers for any given level.

Just play co-op dawg

1P2C in general is not difficult, at least in my opinion. Very rarely are you truly controlling both players at the same time (usually it's just switching between them very quickly), and when you are it's usually very simple movement, such as walking in a straight line.

One of the more involved 1P2C strats I can think of is using both players to force the pillars in Vader room 2, which only saves a couple of seconds. As Blue said though, not all 1P2C is created equal. 1P2C saves over a minute in Chancellor (Both 2 Player Warps plus the Drop-In Warp in the elevator shaft, all of which are pretty easy).

Over the course of the entire run I'd estimate 1P2C to save somewhere between two to three minutes. It's definitely worth trying out, the strats are all very easy to do after a bit of practice.