there are 2 different things to consider here. the straight cut gear, and the dogbox engagement.
there is the fact that the gears are straight cut, this doesnt affect engagement, this is purely sound. straight cut gears can be stronger though.
the second is that it has dogbox engagement. this means there are no syncros only thick “ears” that engage each other. without syncro the input shaft will not spin up like with normal syncros, so you have to rev up the engine or jam it in gear to engage a lower gear.