I’m so sorry about your BFN, I have been there many, many times.
I think it really depends on your RE. My RE lets you do FET’s back to back because they are not that ahrd on your body. But usually RE’s want you to wait a cycle or two in between fresh cycles.
I am always one to be supportive, but I am also one not to give false hope. You cannot think that transferring two is going to work simply because you’re transferring two. The number that you transfer obviously gives you better odds, but it really depends on the environment they are being transferred into as well as the quality of the embryos. My RE explaned it to me like this one time… By looking in a microscope we can tell from the physical characteristics that it “looks” like a good blast…but it’s kind of like buying a car through a show room window. It looks GREAT on the outside, but you don’t know what the engine looks like.
Never lose hope, but be realistic.