I’ve got two games - one a continuation of our playtest game with 4 players and the other a West March Style open world/survival style game with fifteen players. I approach encounter design very differently for them.
The ongoing game is about the narrative (outside of random encounters) and I plan things with that in mind. The West March style game has a large map and the players are free to go anywhere but the further from the Settlement, the more dangerous. In that regard it’s much like an MMO in that different regions are different levels. There’s nothing stopping a low level character from going to the level 20+ area but it’s going to be hella dangerous.