In my experience what causes the slowdown are the people who merged too early who then resentfully close the gap in front of them when people try to merge later than them, simultaneously increasing the likelihood that they’ll rear end the car in front of them and making it harder for the people trying to merge properly to do so.
Just use the lane normally and zipper merge when the lane ends. Don't waste space. Don't block people. You don't get brownie points for being in the "correct" lane as soon as possible, and it doesn't help to police others who are using the existing lane. It really isn't that hard.
A zipper merge is fine, both lanes tend to fill up.
What I often see if a lane that intended to go through and a turning lane that is backed up; people pretend to be on through lane, then stop to merge at last minute into long turning lane and void the line.
