Yes, try this...
My MIL used to freeze Morrell mushrooms.
You can't buy these. You have to hunt them wild during their very short season in May. So, freezing was important if they found a lot.
If I am right, she would wash them and then freeze them completely submerged in containers of water.... (NOT dry, NOT flash frozen).
Then, they would be slowly thawed in the fridge.
I am sure that these were no longer like fresh mushrooms.
But, I would imagine that this would be the best method.
You would probably not put them on a salad like fresh mushrooms. But they might be good for entrees, sauces, etc...