Here are 4 tarpit MX services which can complement the solution to absorb spam being directed at/into the no-email domain, depending on needs:

    # https://wiki.junkemailfilter.com/index.php/Project_Tar
    tar.junkemailfilter.com

    ## https://abusix.com/blackhole-mx/
    void.blackhole.mx

    ## https://www.dnswl.org/?page_id=17
    mail-in.verboten.net

    ## https://fakemx.org/
    mx.fakemx.net