Based on what you said, I assume you are cutting grass that is about 6 to 8' long. If it were mine, I would first cut the grass at the highest setting on the mower, Then in a couple of days go back and cut it to the recommended 3" --3.5". If the highest setting still causes problems I would make the first cut with the mower in the up (Non mowing) position.

First, one assumption - the lawn is actively growing, so the moisture content is pretty high.

For me (42" 2-blade mulching deck mowing 3/4ths of an acre), the "half-deck" approach usually works best. I find that I may have to slow my ground speed a little, but the reduced width helps ensure that the grass is cut cleanly, while further mulching the clippings.

When it's really bad, I've followed knuttle's process, mowing at the highest setting, then coming-back in a few days to mow as usual. I find that I can mow the first time pretty quickly (fast ground speed), so the first pass takes less time than it normally would. The second pass will be at right angles to the first, so the lawn really has a nice look to it.

I mow a 1 acre lot/field w/a jd300 until engine failure forced a move to a 318. Use a lawn sweeper w/a 48" deck. If high, I mow less than full width & the sweeper prevents bulk build up. The deck still discharges & sweeper gets most of what is left. Cut my repeat passes 75% & works for me. On plus side, I have ample supply of clippings for mulch w/o raking.
Doing this as a Property Maintenance biz, preferring a tractor to a zero turn due to most customers having rough mowing areas w/trees, rocks, mostly 1/2 speed max. Not much golf course type mowing.

I tend to go the turtle speed route. I suspect the turtle speed route versus the 1/2 deck route will work out the same and probably take about the same amount of time.

The 1/2 deck route to me is like being stuck on a slow moving freeway so you take an alternate route. Usually the alternate routes will inevitably take longer then the slower moving freeway, but it just feels better to be moving faster.

In any event, I just put the tractor on a slower moving speed, keep the blade sharp and plow through it. I agree though, it does feel like life is a bit too short to cut grass like that, but it does do a good job.