Your full requests demonstrate how well your query is working. Above all, your opening pages are attracting positive commentary (bravo) from agents. You're also approaching this strategically, ie. accepting feedback from fulls, and integrating it into your work. This can only make your novel stronger.
Having a trusted, talented circle of beta readers is invaluable, as I know from personal experience. So what next?
It can feel like one is climbing Mount Everest in slippers, but honestly, that's what this venture is like. Full requests are exhilarating but won't always lead to representation because, as you know, an agent must feel passionate enough about the work to commit to the gruelling sales process. It's never personal, or connected to the literary merits of the manuscript, but relates to marketability. Again, this is a subjective call by the agent. it's also down to timing (right manuscript on the agent's desk, at the right time).
I once submitted to an agent who requested my full, and then, wait for it, sat on it for what seemed like decades (but was only 8 months.) I later discovered this was her habit until publishers said "do you have any books about X and Y? Then, like a magician, she'd produce them. (Not mine
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Finally, you say you will keep going. That's exactly what you must do. This process has its own peculiarly slow and painful timescale so in the meantime, start another work because that truly is the best antidote to frustration while tracking those submissions.
