I have received over the years so much spam of this kind by multiple YC-funded companies that I now reflexively send to spam any email that mentions being YC-funded, regardless of how legitimate the email is.
I don't blame you, the FOMO is real to the point even basic ChatGPT wrappers are getting funded these days, I guess.
Same here, having YC attached to your name is not the flex you think it is, its even the opposite for me