I maybe mis-remembering this, but isn’t there an option when setting up Certbot (or maybe a flag you set at install) that doesn’t earn you the cron job? When I crontab -e as both myself and root I don’t see one in any case. I really just followed a tutorial and was pasting in snippets…
I honestly didn’t expect any of this to work as well as it has, so I seem to recall not committing fully at the install stage. 