I'm an early career researcher in my second year of PhD -— but by all accounts this is the rule not the exception. I had a strong PhD research proposal which earned me a scholarship (and that I was very attached to) but to my surprise all my supervisors and some other academics really pushed me to explore beyond that idea -ultimately— ultimately with me developing something far more unique which was only tangentially related to my initial proposal. However, where I landed is far closer to a deeper line of inquiry that ultimately brought me to academia in the first place. In many ways, I'd developed my initial research proposal because I thought it made a "strong research proposal" -— but I'd neglected to consider how deeply it engaged me. My supervisors kept questioning "who is this research for?" and "go wild" and offering that the best new knowledge comes from deeper and perhaps more personal lines of inquiry.
Read the literature for inspiration, don't get obsessed looking for "the gap"
"the gap" or you'll never see it. Eureka moments don't occur under duress. Sometimes when you feel like you've been left with nothing, you're in a more optimal position to take more risk. Risk is the most liberating thing for finding new knowledge. Good luck!