As someone who works in finance, I would disagree. I asked ChatGPT:

    Is the noun spend rare?

    ChatGPT said:
    The noun "spend" is relatively rare compared to its more common form as a verb. While "spend" is widely used as a verb (meaning to give money or time for something), as a noun, it refers to an expenditure or the act of spending, and it’s not as commonly encountered.

    In most contexts, people would use alternatives like "expenditure," "spending," or "outlay" instead of "spend" as a noun. That said, it is still used occasionally in certain contexts, especially in financial or informal language.