Currently, there are very few monsters that can be level 30 or above in the public beta version of "Diablo 4". Please see below how to efficiently farm level 30 monsters in Diablo 4.
This part of the map is a fortress. After it is occupied, it will become a 30+ monster map. The drops in it are all based on the drops of 30+ monsters. Whatever drops will kill the garbage in other places. The affix will be directly one level higher. .