I think the best way to do have trash mobs lies in the execution of the open world model. If open world is done correctly, in my opinion, you can find low level quests in most areas throughout the world. This gives a realness to the world instead of a "Done with level 1-5 level area time for the 6-10" which sort of breaks immersion and promotes a more linear exploration. I love to discover an area that seems impossible and then come back later when the party is leveled, or going into a high level area and searching for any quests that I might be able to do. This kind of design not only allows for different leveling experiences but also provides the trash mobs and trash quests. BG3 seems to be doing a good job with this atm but the real test to there open world design comes after we leave this first area and how soon we can leave it.
