I'm so happy not all games are like this, I abhor hidden or unfair mechanics. Even if you sometimes get one-shotted "out of the blue" in, say, Path of Exile, you can be sure game didn't "help" you, there is a crystal clear explanation of every mechanic in Wiki and your 90 lvl hardcore char IS your and your skill achievement.
Every game mist do this, of course. Hitboxes are not (and can't be, and shouldn't be) perfectly accurate reflections of the target. Firing arcs are compressed down to the resolution of the game. Random chances aren't really random. Etc.
what game designers realized long ago is that tuning these necessary approximations makes for a better game if 'more fun' is a stronger criteria than 'more accurate simulation of a usually-imaginary situation'.
My usual example of this is critical hits in multiplayer games (I usually use WoW and D&D as examples, because they're well known). In D&D there is a chance that each attack is a critical success - an extra good hit. In the simplest versions, this is the 20 result on the 20-sided die, which means that roughly 5% of the time, on average, you get a critical. In WoW, crits do the same thing, but the rule is 'every so often', rather than '1 in 20 chance each try'. The designers of WoW understand that humans like these things to be "unpredictable but fair", so they have effectively a timer for crits; if you don't get a critical hit in a certain elapsed time, your chance goes up, until eventually it reaches certainty. This makes critical hits regular but. It predictable.
If the game has dynamic difficulty mechanics but applies them fairly to everyone playing, isn't your relative success or failure compared to other players still a matter of skill?