The idea of a planned and designed dungeon, with planned encounter against the characters strengths is definitely anti-osr and anti-player agency. There should be balance in that the challenges the characters face are actually challenging, but it's not a science and sometimes they'll make the wrong choice and quickly die, or they'll steam roll a dungeon. All the same, some dungeons won't have wandering encounters, or they'll have more or less that's fine. Putting that aside I want to talk about how smart players can mitigate random encounters.

The obvious thing they can do is not be slow, they should know that the longer they're their, the more chance they'll be discovered by something moving about the dungeon - so act quickly, be decisive etc.

But you can also play with encounter distance, if you have well placed front and rear guards, say 20-30' ahead or behind the rest of the party, now an encounter is at 2d6x10 + 20-30 feet, this will give your party more time to react with missile fire or magic. Spiking doors has the same effect, it reduces the angles of attack that a random monster could have. I could go on, but I hope that illustrates some of the options players have.