Can AI tell me whether someone has already done my idea?
Tyra Banks described using AI to look for ideas like her own before spending time and money on a pitch. That works as a research assignment. An AI answer still can't prove your idea is unique.
I'd ask for comparable examples with source links and the date of each. Ask what was searched and which parts of your question are still unanswered.
The closest example may not be the first one
A product with a similar name may solve a different problem. A project in another country may sit much closer to your concept than the first search result suggests. Describe the overlap before you decide what makes your idea different.
Keep "nothing relevant found in this search" apart from "nothing like this exists." The first describes the evidence you have, and the second claims more than one search can establish.
If the decision involves intellectual property rights, AI research can't serve as legal clearance, and that question goes to the appropriate professional.
What to try this week
Before your next pitch, build a short comparison of the closest examples and write down the difference your intended customer would notice.