I use a box cutter actually. Works fine for most things.
If efficiency is your aim it might be worth it to spend the money on better materials with less inconsistency.
I also tend to use a bit more power when I really need to be sure that cuts are going to work. It’s a bit slower but it’s worth it not to have to fiddle with it after the fact.
I also design my cut sheets to have 10% or so extra pieces, so I automatically build in some loss. With most materials the cost per square inch is just not worth worrying about it… all depends on how you value your time. I’m super expensive per hour, so I’d rather lose 5-10% of my materials instead of having to do extra labor to try to finish janky cuts.