Suddenly, I felt that I was a fish out of water and I didn’t know how to spend the much spare time.
Does the sentence above look fine to you? Not to me. I think "much" does not work there, because I don't see "much" as an adjective in the dictionary. However, another sentence popped into my head:
I don't have much time.
This "much" looks like an adjective.
What do you think? Thanks.