What changes if I use fresh mushrooms, rather than dried, to make Chinese mushroom soup (冬菇湯)? I'll be shunning meat. Note that unlike Western mushroom soups, mushrooms aren't blended in Chinese soups.
Fresh/raw mushrooms are quite bland by themselves (yes I know there are exceptions).
I suggest pan fry in oil them before using them in the soup, or chop them up and bake them in the oven on a sheet pan.
When you are using dried mushroom, you will re-hydrate them in water and you will usually use the resulting liquid which contains a lot of flavor in the recipe.