I recently completed my first manuscript. It is a story that was burning within me to tell, though it is of an entirely different genre than what I see myself writing in the future. This manuscript is a psychological thriller, and I see myself writing fantasy (perhaps with a mix of mystery or thriller).
Would you advise querying for the thriller knowing I don't plan on writing that specific genre? I don't want to waste an agent's time, nor do I want to be pigeonholed into a genre I may have less love for than others. The logic in my mind says I should wait until a second, more genre-accurate (fantasy) manuscript is finished and start by querying that one, rather than jump the gun and query the thriller just to be a published author.
There's a great truism from our guys in the military: "No plan survives boots on the ground."
Yours is a classic example of thinking too far ahead to be useful.
You're assuming your thriller will be publishable and published. That's not a given.
You're assuming the unstarted/unfinished fantasy manuscript will get finished, and published. That's not a given. That's not even a reasonable bet at this point in time.
Right now the best thing to do is finish a book and query it. You'll learn a lot in the process and that information will be useful when you decide what to do for your second book.
Short answer: don't get ahead of yourself or you'll end up chasing your tail.
PS Don't ever think you're wasting my time by offering to let me read your work. Not now. Not ever. You're a writer. I'm an agent. In the immortal words of the elegant John Keats "that is all
Ye know on earth, and all ye need to know.'"